title: Rails 4 and paperclip - Stop the :original style file upload to copy it from an S3 remote directory
body: <p>I use Paperclip 4.0.2 and in my app to upload pictures.</p>
  
  <p>So my Document model has an attached_file called <code>attachment</code></p>
  
  <p>The attachment has few styles, say <code>:medium, :thumb, :facebook</code></p>
  
  <p>In my model, I stop the styles processing, and I extracted it inside a background job.</p>
  
  <pre><code>class Document &lt; ActiveRecord::Base
  # stop paperclip styles generation    
  before_post_process
    false
  end
  </code></pre>
  
  <blockquote>
    <p><strong>But the :original style file is still uploaded!</strong></p>
  </blockquote>
  
  <p>I would like to know if it's possible to stop this behavior and copy the file inside the :original/filename.jpg from a remote directory
  My goal being to use a file that has been uploaded in a S3 /temp/ directory with jQuery File upload, and copy it to the directory where Paperclip needs it to generate the others styles.</p>
  
  <p>Thank you in advance for your help!</p>