title: Django cascade delete on reverse foreign keys
body: <p>Django shows how to set or override cascade deletes with foreign keys in their documents. </p>
  
  <pre><code>model = models.ForeignKey(MyModel, null = True, on_delete = models.SET_NULL)
  </code></pre>
  
  <p>But what if we wanted this effect the other way around? What if we want the deletion of the fk model to result in the deletion of this model?</p>
  
  <p>Thanks</p>