title: Django admin filter rows based on permissions
body: <p>In the Django admin, I would like to display only certain rows of a model based on the user.</p>
  
  <pre><code>class Article(models.Model):
      text =          models.TextField(max_length=160)
      location =        models.CharField(max_length=20)
  </code></pre>
  
  <p>So, when a user logs into the admin site, and is part of the San Francisco <code>location</code>, they should only be able to see <code>Articles</code> with that location. </p>