title: Django: when creating custom user, ValueError: Dependency on unknown app
body: <p>I'm building a brand-new web project with Python 3.4.3 and Django 1.8 without any migrations made so far. For the project, I'm creating a custom user inheriting from <code>AbstractBaseUser</code> in an app called <code>users</code>. I've also correctly referred <code>AUTH_USER_MODEL</code> to the custom user in <code>settings.py</code>, before creating any migrations, as mentioned in the <a href="https://docs.djangoproject.com/en/1.8/topics/auth/customizing/#substituting-a-custom-user-model" rel="nofollow">doc</a>. </p>
  
  <p>However, when I tried to run <code>python manage.py makemigrations users</code> or <code>python manage.py migrate</code>, the console reports <code>ValueError: Dependency on unknown app: users</code>. </p>
  
  <p>I'm pretty sure my code for the custom user model is correct because I followed documentation's example code, and also because, when I commented out <code>AUTH_USER_MODEL</code>, everything else worked fine except that Django created tables for the default User model, which is expected.</p>
  
  <p>In the <a href="https://docs.djangoproject.com/en/1.8/topics/auth/customizing/#substituting-a-custom-user-model" rel="nofollow">documentation</a> it is mentioned that:</p>
  
  <blockquote>
    <p>you must ensure that the model referenced by AUTH_USER_MODEL is created in the first migration of its app (usually called 0001_initial); otherwise, you will have dependency issues.</p>
  </blockquote>
  
  <p>I'm not very sure what exactly this means. Does it mean that I have to manually create a migration for my <code>users</code> app? If so, how exactly should I do it?</p>
  
  <p>I greatly appreciate any suggestion or redirection to a credible source! Thank you very much in advance!</p>