Dev/dev env default secret token

I'm not a ruby developer but struggle with this while setting my dev environment while running "rails s" I had it throw those warnings on the console and browser which restricted the ajax response to be handled correctly:

```
DEPRECATION WARNING: You didn't set config.secret_key_base. Read the upgrade documentation to learn more about this new config option. (called from env_config at /home/emad/.rvm/gems/ruby-2.1.4/gems/railties-4.0.1/lib/rails/application.rb:141)
2014-12-14 13:42:17 -0500: Rack app error: #<RuntimeError: You must set config.secret_key_base in your app's config.>
/home/emad/.rvm/gems/ruby-2.1.4/gems/railties-4.0.1/lib/rails/application.rb:145:in `env_config'
/home/emad/.rvm/gems/ruby-2.1.4/gems/railties-4.0.1/lib/rails/engine.rb:507:in `call'
/home/emad/.rvm/gems/ruby-2.1.4/gems/railties-4.0.1/lib/rails/application.rb:97:in `call'
/home/emad/.rvm/gems/ruby-2.1.4/gems/rack-1.5.2/lib/rack/content_length.rb:14:in `call'
/home/emad/.rvm/gems/ruby-2.1.4/gems/puma-2.6.0/lib/puma/server.rb:486:in `handle_request'
/home/emad/.rvm/gems/ruby-2.1.4/gems/puma-2.6.0/lib/puma/server.rb:357:in `process_client'
/home/emad/.rvm/gems/ruby-2.1.4/gems/puma-2.6.0/lib/puma/server.rb:250:in `block in run'
/home/emad/.rvm/gems/ruby-2.1.4/gems/puma-2.6.0/lib/puma/thread_pool.rb:92:in `call'
/home/emad/.rvm/gems/ruby-2.1.4/gems/puma-2.6.0/lib/puma/thread_pool.rb:92:in `block in spawn_thread'
```

when I looked it up, I read about this on stackoverflow but not sure if this is the right way.

**ideally** It would be helpful to clarify it on the "contribution" section on manshar.
I noticed the database.yml.sample but not environment one.
Maybe we could add it to make it less hassle to contribute for non-ruby developers.