title: Replacing variable in :url for wicked_pdf
body: <p>I have the following defintion in wicked pdf to render the footer</p>
  
  <blockquote>
  <pre><code>   :footer =&gt; {:html =&gt; { :url =&gt; 'http://www.descher.at/test.html' },
  </code></pre>
  </blockquote>
  
  <p>What I want to do is to replace the values of [page] and [topage] as added in the
  html to the real values. </p>
  
  <p>Is this possible using the given reference :url, if yes, what is the correct way of embedding
  the respective variable in the html to be embedded?</p>
  
  <p>thanks</p>