title: Django display charfield field that represents minutes as hh hours, mm minutes
body: <p>I have a field in Django that is a <code>models.CharField</code> .</p>
  
  <p>It stores the duration of a movie.</p>
  
  <p>For a movie that lasts 90min, when I call it from a template, something like </p>
  
  <pre><code>{{ movie.duration }}
  </code></pre>
  
  <p>I would like to get 1 hour, 30 minutes instead of 90min.</p>