title: Deleting unused Models, stale content types prompt
body: <p>I am removing an unnecessary table and model from our Django website. I have removed all foriegn key references before the migrations.DeleteModel(...) is called, but I still am receiving the following prompt when I run the migration:</p>
  
  <blockquote>
    <p>The following content types are stale and need to be deleted:</p>
  
  <pre><code>myapp | MyDeletedModel
  </code></pre>
    
    <p>Any objects related to these content types by a foreign key will also
    be deleted. Are you sure you want to delete these content types? If
    you're unsure, answer 'no'.</p>
  
  <pre><code>Type 'yes' to continue, or 'no' to cancel: yes
  </code></pre>
  </blockquote>
  
  <p>I am confused why I am receiving this prompt is there a way I can stop this prompt from showing when we go live? we use a CI environment where we do not have users available to answer "yes" or "no"</p>
  
  <p>Thanks</p>