title: custom nested routes with Kohana 3
body: <p>I have a Articles model and a Category model, both with a <code>url_slug</code> variable (what I would like to show up in the url when looking for it. here is how I would like to have the URLs appear:</p>
  
  <pre><code>//list all of the articles
  http://example.com/articles   
  
  //list of all the articles in that category
  http://example.com/articles/:category_slug 
  
  //a single article.
  http://example.com/articles/:category_slug/:article_slug
  </code></pre>
  
  <p>How should I set up the articles controller and/or the routes in order to achieve this?</p>