ActionView::Template::Error: undefined method `is_admin' for nil:NilClass

Question

I am using ruby 2.2/Rails 4.2 and active record on Heroku. I am getting this error on my heroku production server only. Everything works fine on my dev machine. is_admin is a boolean field I added to my Devise user table, and is checked when a logged in user tries to load a page in the admin section. If they are not an admin they get kicked to the main app page. The strange thing is that its the login page that gives this error, and is_admin shouldn't be getting called unless a) the user is logged in (Im not) and b) the user tried to load an admin page (I did not).

I installed delayed_jobs based on some advice in another thread. I got that working (I think, it at least doesn't crash my dev server) but I am still getting the same undefined_method error.

May 08 06:45:25 myappname heroku/router:  at=info method=GET path="/portal/users/sign_in" host=myappname.herokuapp.com request_id=946f39d1-7f07-4d52-a436-66c14c6734bc fwd="68.196.133.101" dyno=web.1 connect=2ms service=2943ms status=500 bytes=153 
May 08 06:45:25 myappname app/web.1:  2015-05-08 13:45:24 +0000: Rack app error: #<ActionView::Template::Error: undefined method `is_admin' for nil:NilClass> 
May 08 06:45:25 myappname app/web.1:  /app/app/views/layouts/application.html.erb:71:in `_app_views_layouts_application_html_erb___400859338153902421_70022501785140' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/template.rb:145:in `block in render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:166:in `instrument' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/template.rb:333:in `instrument' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/template.rb:143:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/renderer/template_renderer.rb:66:in `render_with_layout' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/renderer/template_renderer.rb:52:in `render_template' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/renderer/template_renderer.rb:14:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/renderer/renderer.rb:42:in `render_template' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/renderer/renderer.rb:23:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/rendering.rb:100:in `_render_template' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/streaming.rb:217:in `_render_template' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/rendering.rb:83:in `render_to_body' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rendering.rb:32:in `render_to_body' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/renderers.rb:37:in `render_to_body' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/rendering.rb:25:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rendering.rb:16:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:41:in `block (2 levels) in render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/core_ext/benchmark.rb:12:in `block in ms' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/ruby-2.2.0/lib/ruby/2.2.0/benchmark.rb:303:in `realtime' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/core_ext/benchmark.rb:12:in `ms' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:41:in `block in render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:84:in `cleanup_view_runtime' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/controller_runtime.rb:25:in `cleanup_view_runtime' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:40:in `render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/implicit_render.rb:10:in `default_render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/responders-2.1.0/lib/action_controller/responder.rb:236:in `default_render' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/responders-2.1.0/lib/action_controller/responder.rb:170:in `to_html' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/responders-2.1.0/lib/action_controller/responder.rb:163:in `respond' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/responders-2.1.0/lib/action_controller/responder.rb:156:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/responders-2.1.0/lib/action_controller/respond_with.rb:203:in `respond_with' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/devise-3.4.1/app/controllers/devise/sessions_controller.rb:11:in `new' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/implicit_render.rb:4:in `send_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/base.rb:198:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rendering.rb:10:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/callbacks.rb:20:in `block in process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:117:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:117:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:234:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:169:in `block in halting' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `block in halting_and_conditional' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `block in halting_and_conditional' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `block in halting_and_conditional' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:151:in `block in halting_and_conditional' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:92:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:92:in `_run_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:734:in `_run_process_action_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:81:in `run_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/callbacks.rb:19:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rescue.rb:29:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:31:in `block in process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:164:in `block in instrument' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications/instrumenter.rb:20:in `instrument' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/notifications.rb:164:in `instrument' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/instrumentation.rb:30:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/params_wrapper.rb:250:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/railties/controller_runtime.rb:18:in `process_action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/abstract_controller/base.rb:137:in `process' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionview-4.2.0/lib/action_view/rendering.rb:30:in `process' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal.rb:195:in `dispatch' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal/rack_delegation.rb:13:in `dispatch' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_controller/metal.rb:236:in `block in action' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:73:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:73:in `dispatch' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:42:in `serve' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/mapper.rb:49:in `serve' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/journey/router.rb:43:in `block in serve' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/journey/router.rb:30:in `each' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/journey/router.rb:30:in `serve' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/routing/route_set.rb:802:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/warden-1.2.3/lib/warden/manager.rb:35:in `block in call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/warden-1.2.3/lib/warden/manager.rb:34:in `catch' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/warden-1.2.3/lib/warden/manager.rb:34:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/etag.rb:24:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/conditionalget.rb:25:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/head.rb:13:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/params_parser.rb:27:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/flash.rb:260:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/session/abstract/id.rb:225:in `context' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/session/abstract/id.rb:220:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/cookies.rb:560:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/query_cache.rb:36:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activerecord-4.2.0/lib/active_record/connection_adapters/abstract/connection_pool.rb:647:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/callbacks.rb:29:in `block in call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:88:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:88:in `_run_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:734:in `_run_call_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/callbacks.rb:81:in `run_callbacks' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/callbacks.rb:27:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/remote_ip.rb:78:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/show_exceptions.rb:30:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.0/lib/rails/rack/logger.rb:38:in `call_app' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.0/lib/rails/rack/logger.rb:20:in `block in call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/tagged_logging.rb:68:in `block in tagged' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/tagged_logging.rb:26:in `tagged' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/tagged_logging.rb:68:in `tagged' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.0/lib/rails/rack/logger.rb:20:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/request_id.rb:21:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/methodoverride.rb:22:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/runtime.rb:18:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/activesupport-4.2.0/lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/lock.rb:17:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/actionpack-4.2.0/lib/action_dispatch/middleware/static.rb:113:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/rack-1.6.1/lib/rack/sendfile.rb:113:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.0/lib/rails/engine.rb:518:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/railties-4.2.0/lib/rails/application.rb:164:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/configuration.rb:51:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/server.rb:507:in `handle_request' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/server.rb:375:in `process_client' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/server.rb:262:in `block in run' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/thread_pool.rb:104:in `call' 
May 08 06:45:25 myappname app/web.1:  /app/vendor/bundle/ruby/2.2.0/gems/puma-2.11.2/lib/puma/thread_pool.rb:104:in `block in spawn_thread' 

Answer 1

You are probably calling the is_admin? in the layout. Perhaps in the sidebar, without having a current_user logged in. Try adding:

if current_user && current_user.is_admin?

To the validation to ensure there is a current_user before doing the is_admin? validation.