title: file download link in rails
body: <p>I would like to give visitors the option to download some pdf. 
  I have tried:</p>
  
  <pre><code>&lt;%= link_to "abc", "/data/abc.pdf"%&gt;
  
  &lt;%= link_to "abc", "/data/abc.pdf", :format =&gt; 'pdf' %&gt;
  </code></pre>
  
  <p>and some variations but they don't seem to work. I keep getting <code>No route matches [GET] "/data/abc.pdf"</code></p>
  
  <p>I have the pdf files in a folder called data, located in the assets folder.
  Any help would be appreciated.</p>