Rails Server producing error on Home Page after rails 5 upgrade

Question

I have attempted to upgrade from rails 4.2 to 5. my ruby version and rails version are now both upgraded, and I've attempted to run through what I believe to be most of the upgrade steps. When I run rails server, the server will boot up but when I access localhost:3000, the browser throws an error.

The odd thing is that the terminal/log does not throw any error at all. I see this in the log:

iMac:appDirectory name$ rails server
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/default_style_key.rb:10)
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/show_root_alone.rb:11)
DEPRECATION WARNING: alias_method_chain is deprecated. Please, use Module#prepend instead. From module, you can access the original method using super. (called from block in <top (required)> at /Users//.rvm/gems/ruby-2.4.0@global/gems/gretel-3.0.8/lib/gretel/deprecated/yield_links.rb:19)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::HTML` to `Mime[:html]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::TEXT` to `Mime[:text]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
DEPRECATION WARNING: Accessing mime types via constants is deprecated. Please change `Mime::URL_ENCODED_FORM` to `Mime[:url_encoded_form]`. (called from <class:Request> at /Users//.rvm/gems/ruby-2.4.0@global/gems/web-console-2.2.1/lib/web_console/request.rb:7)
=> Booting WEBrick
=> Rails 5.0.1 application starting in development on http://localhost:3000
=> Run `rails server -h` for more startup options
[2017-02-26 00:51:50] INFO  WEBrick 1.3.1
[2017-02-26 00:51:50] INFO  ruby 2.4.0 (2016-12-24) [x86_64-darwin15]
[2017-02-26 00:51:50] INFO  WEBrick::HTTPServer#start: pid=xxxxx port=3000
Started GET "/" for ::1 at 2017-02-26 00:51:57 -0600

I believe this may just be something dumb i'm forgetting (and not relevant to the rails 5 upgrade at all) but I'm a bit stumped as I can't see any error messages even though localhost:3000 throws:

We're sorry, but something went wrong.

If you are the application owner check the logs for more information.

thanks for any assistance...

Answer 1

Updating web-console gem as per Shabini's comment did the trick.