title: asset_sync not calling md5 hashed asset with Rails 3
body: <p>I was wondering if anyone could see anything wrong with my asset_sync config, when uploading to my bucket the original and the md5-hash version are being uploaded, instead of just the hashed version, is this correct?</p>
  
  <pre><code>Using: Manifest /tmp/build_9c7add81-9978-4a01-b46b-f9a4c5ef032e/public/assets/manifest.yml
     Overwriting matching file assets/arrow-left-06560809407b138d1da196208f851494.png with custom headers {:cache_control=&gt;"max-age=31536000", :expires=&gt;"Tue, 16 Jun 2015 10:16:23 GMT"}
     Uploading: assets/arrow-left-06560809407b138d1da196208f851494.png
     Overwriting matching file assets/arrow-right-ae6596cd5b8613bc8dc71cac6851f769.png with custom headers {:cache_control=&gt;"max-age=31536000", :expires=&gt;"Tue, 16 Jun 2015 10:16:23 GMT"}
  </code></pre>
  
  <p>Also when trying to call the assets, it is calling the original filename not the md5 hash, so</p>
  
  <pre><code>&lt;img src="http://mybucket.s3.amazonaws.com/assets/slider/img-6.jpg"&gt;
  </code></pre>
  
  <p>instead of </p>
  
  <pre><code>&lt;img src="http://mybucket.s3.amazonaws.com/assets/slider/img-6-06560809407b138d1da196208f851494.jpg"&gt;
  </code></pre>
  
  <p>My initializer looks like this</p>
  
  <pre><code>if defined?(AssetSync)
  AssetSync.configure do |config|
    config.fog_provider = ENV['FOG_PROVIDER']
    config.aws_access_key_id = ENV['AWS_ACCESS_KEY_ID']
    config.aws_secret_access_key = ENV['AWS_SECRET_ACCESS_KEY']
    config.fog_directory = ENV['FOG_DIRECTORY']
    config.fog_region = ENV['FOG_REGION']
  
  
   config.existing_remote_files = "delete"
   config.gzip_compression = true
   config.manifest = true
   config.custom_headers = { '.*' =&gt; { cache_control: 'max-age=31536000', expires: 1.year.from_now.httpdate } }
   end
   end
  </code></pre>
  
  <p>When i deploy to heroku rake:assets precompile is run, but i have run locally aswell so wondering if ,y manifest.yml file is incorrect? can i delete this and create a new one?</p>
  
  <p>If any more info is needed then please let me know</p>
  
  <p>Thanks</p>
  
  <p>EDIT</p>
  
  <p>So i have found the reason why the original file and the finger printed asset gets created</p>
  
  <p>"Rails 3 by default compiles once to generate fingerprinted assets, and once to generate non-fingerprinted assets (the fingerprinted ones have the MD5 hash in the filename).</p>
  
  <p>You can use the turbo-sprockets-rails3 gem to create both from one compilation.</p>
  
  <p>In Rails 4, this functionality was extracted into the sprockets-rails gem and the behavior was changed, so the double compilation does not happen in Rails 4."</p>
  
  <p>At this stage though i still dont know why the finger printed asset is not being called</p>