I can not get rails server to run on cloud9

When I run rails server this is the issue that I get: rails server -b $IP -p $PORT

=> Booting WEBrick

=> Rails 4.2.1 application starting in development on http://0.0.0.0:8080

=> Run rails server -h for more startup options

=> Ctrl-C to shutdown server

Exiting

/usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/server.rb:142:in log_to_stdout': undefined methodformatter' for nil:NilClass (NoMethodError)

    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/server.rb:78:in `start'
    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:80:in `block in server'
    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `tap'
    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:75:in `server'
    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /usr/local/rvm/gems/ruby-2.2.1/gems/railties-4.2.1/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

I made adjustments to the config.ru file however that did not work so I changed it back. How do i fix this problem?