When i try to include
<%= stylesheet_link_tag \"application\" %>
<%= javascript_include_tag \"application\" %>
The content
I was also having this issue but with newer versions of Rails and Ruby.
Examining the log, I was being served javascript.js from Rails cache as the server didn't see a change in the file. I went and moved the require lines around (just one) to tell Rails that there's a change in the file and re-compile/use. Wellm that did it for me!
Hope it helps somebody.
Another important finding is to upgrade your sprockets gem in your Gemfile.
I had version 2.2.1 and had issues, after upgrading to 2.2.2, it worked
gem 'sprockets', '2.2.2'