title: Cannot read file with send_file function in Rails 3
body: <p>The code I am using:</p>
  
  <p>In view file:</p>
  
  <pre><code> &lt;%= link_to "Download", download_image_path(image) %&gt;
  </code></pre>
  
  <p>In controller:</p>
  
  <pre><code>def download
    @image = Image.find(params[:id])
    send_file "#{RAILS_ROOT}/public"  + @image.attachment.url
  end
  </code></pre>
  
  <p>I am getting an error:</p>
  
  <pre><code>Cannot read file /Users/mohit/projects/my_app/public/system/attachments/4/original/Screen Shot 2011-11-04 at 3.14.03 PM.png?1320582022
  </code></pre>
  
  <p><em>PS: double checked, the file exists. Same issue on server, for all the files (images, pdfs, videos) in all the respective controllers.</em></p>