title: Django2.0.7 TypeError: Model instances without primary key value are unhashable
body: <p>I am trying to migrate the models that were generated for me via <code>python manage.py inspectdb</code>. I tried <code>python manage.py makemigrations</code> and got this error: </p>
  
  <blockquote>
    <p>SystemCheckError: System check identified some issues:<br>
    ERRORS:<br>
    Users.DjangoContentType: (models.E004) 'id' can only be used as a field name if the field also sets 'primary_key=True'.</p>
  </blockquote>
  
  <p>So I went into my file and changed this model:
  <a href="https://i.stack.imgur.com/4NICU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4NICU.png" alt="enter image description here"></a></p>
  
  <p>To this:
  <a href="https://i.stack.imgur.com/B1kNO.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/B1kNO.png" alt="enter image description here"></a></p>
  
  <p>and when I run <code>python manage.py makemigrations</code> and <code>python manage.py migrate</code> and I get this error:</p>
  
  <p><a href="https://i.stack.imgur.com/VxQtD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VxQtD.png" alt="enter image description here"></a></p>
  
  <p>Any idea what I should do/what this means?</p>
  
  <p>This is my pip freeze output:</p>
  
  <pre><code>certifi==2018.10.15
  Django==2.0.7
  mysqlclient==1.3.13
  pytz==2018.7
  </code></pre>