title: django importing AUTH_USER_MODEL
body: <p>I´m trying to use settings.AUTH_USER_MODEL as a foreignkey in a model, but the "settings" part doesn´t seem to work.</p>
  
  <p>How should I import that?</p>
  
  <pre><code>from django.contrib.auth.models import User
  
  class Tareas(models.Model):
      creador = models.ForeignKey(settings.AUTH_USER_MODEL, help_text="Estatus del contenido", blank=True, null=True, on_delete=models.CASCADE)
  </code></pre>
  
  <p>Thanks!</p>