title: Javascript manifest file "application.js" is not processed
body: <p>I am on a Macbook Pro and I created a new Rails 3.2 app, but the assets pipeline does not work. Here is what I did:</p>
  
  <pre><code>$ rails version
    Rails 3.2.5
  $ rails new test_assets
  $ cd test_assets
  $ rails server
  </code></pre>
  
  <p>The server is started OK, but if I visit <code>http://0.0.0.0:3000/assets/application.js</code>, it turns out the manifest file is not processed at all, it shows:</p>
  
  <pre><code>//... some comments ...
  //= require jquery
  //= require jquery_ujs
  //= require_tree .
  ;
  </code></pre>
  
  <p>I tried to do the exactly the same steps on my other Macbook Pro. It works well. Visiting <code>http://0.0.0.0:3000/assets/application.js</code> on that machine shows a compiled javascript file with all the contents.</p>
  
  <p>I have read <a href="http://railscasts.com/episodes/279-understanding-the-asset-pipeline" rel="noreferrer">http://railscasts.com/episodes/279-understanding-the-asset-pipeline</a> and <a href="http://guides.rubyonrails.org/asset_pipeline.html" rel="noreferrer">http://guides.rubyonrails.org/asset_pipeline.html</a>, and I searched for hours on the web but with no clue.</p>
  
  <p>Your help is really appreciated!</p>