title: How to refer to root path in Sinatra views
body: <p>Is there a way to refer to the root URL of my Sinatra app? Say in one of the views I'd like to do the following:</p>
  
  <pre><code>&lt;a href="&lt;%= ROOT_PATH/cats %&gt;"&gt;Show all cats&lt;/a&gt;
  </code></pre>
  
  <p>Does Sinatra provide a magic helper for <code>ROOT_PATH</code> or it's equivalent?</p>