title: Paperclip S3 error, No route matches [GET] "/assets/:s3_domain_url"
body: <p>I'm trying to use Paperclip with S3 in my Rails app. But whenever I try to upload a file, I get a 404 error saying <code>No route matches [GET] "/assets/:s3_domain_url"</code>. </p>
  
  <p>This is how I have set up Paperclip defaults in config/environments/development.rb:</p>
  
  <pre><code>config.paperclip_defaults = {
      :storage =&gt; :s3,
      :s3_credentials =&gt; {
         :bucket =&gt; ENV['S3_BUCKET_NAME'],
         :access_key_id =&gt; ENV['AWS_ACCESS_KEY_ID'],
         :secret_access_key =&gt; ENV['AWS_SECRET_ACCESS_KEY']
     }
  }
  </code></pre>
  
  <p>these are the Paperclip settings in the model</p>
  
  <pre><code>has_attached_file :photo, :styles =&gt; { :medium =&gt; "300x300&gt;", :thumb =&gt; "100x100&gt;" }, :default_url =&gt; "/assets/profile/iama.png"
  validates_attachment :photo, :size =&gt; { :in =&gt; 0..1000.kilobytes }
  validates_attachment_content_type :photo, :content_type =&gt; /image/ 
  </code></pre>
  
  <p>Can you help me please?
  Thanks</p>