`parse_rackup_file': rackup file (config.ru) not readable (ArgumentError)

Question

I have this "web: bundle exec unicorn -p $PORT -c ./config/unicorn.rb" in my procfile.

After starting the server i am getting the below error message.

foreman start
12:29:20 web.1  | started with pid 4876
12:29:20 web.1  | exited with code 1
12:29:20 system | sending SIGTERM to all processes
12:29:20        | /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/lib/unicorn/configurator.rb:659:in `parse_rackup_file': rackup file (config.ru) not readable (ArgumentError)
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/lib/unicorn/configurator.rb:77:in `reload'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/lib/unicorn/configurator.rb:68:in `initialize'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/lib/unicorn/http_server.rb:108:in `new'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/lib/unicorn/http_server.rb:108:in `initialize'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/bin/unicorn:126:in `new'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/gems/unicorn-4.7.0/bin/unicorn:126:in `<top (required)>'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/bin/unicorn:19:in `load'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/bin/unicorn:19:in `<main>'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-  p448@cpi2/bin/ruby_executable_hooks:15:in `eval'
12:29:20        |   from /home/stcadmin/.rvm/gems/ruby-1.9.3-p448@cpi2/bin/ruby_executable_hooks:15:in `<main>'
12:29:20        | master failed to start, check stderr log for details

My current application is in Rails 2.3.18.

Answer 1

add something like "-E development -D" in the end.