title: Not recognizning ENV variables in S3.yml in rails
body: <p>I'm currently trying to configure Paperclip with newest <code>aws-sdk</code> suggested gem. </p>
  
  <p>On my S3.yml file I have something like this</p>
  
  <pre><code>development:
    bucket: newmeeter-dev
    access_key_id: ENV['S3_KEY']
    secret_access_key: ENV['S3_SECRET']
  </code></pre>
  
  <p>But it is not recognizing the ENV variables. I'm getting the following error</p>
  
  <pre><code>AWS::S3::Errors::InvalidAccessKeyId in PhotosController#create
  
  The AWS Access Key Id you provided does not exist in our records.
  </code></pre>
  
  <p>If I try to put both the access and secret directly into the file it works perfectly. At the same time I tried to print both ENV variables into the views or in the console I can see their values okay. </p>
  
  <p>I'm not getting why it is not recognizing it. </p>