If every auth_user (or auth.User) will be or have the opportunity to be enrolled on a course I would create a 'user profile' model that has a 1-to-1 relationship with the django User model. You can store additional User data in this model, including what course they are enrolled on. See https://docs.djangoproject.com/en/dev/topics/auth/customizing/#extending-the-existing-user-model for more details but here is an example:
class UserProfile(models.Model):
user = models.OneToOneField('auth.User')
course = models.ForeignKey('courseapp.Course', null=True)
You would probably need to create a signal that gets fired each time an auth.User object is saved, such that if it is the first time that User object has been saved, it automatically creates the UserProfile:
from django.contrib.auth.models import User
from django.db.models.signals import post_save
from yourusersapp.models import UserProfile
def create_user_profile(sender, instance, created, **kwargs):
# Automatically creates a UserProfile on User creation.
if created:
UserProfile.objects.create(user=instance)
post_save.connect(create_user_profile, sender=User)
When you query a User object, you can then reference the User object's profile like:
user_object.userprofile
You could then create a Course object and link the user_object indirectly via its UserProfile to that Course:
course = Course.objects.create(name='course_name', next_field='whatever')
user_profile = user_object.userprofile
userprofile.course = course
userprofile.save()
Now you have a user object with a UserProfile that is linked to only 1 course. Many users can be on the same course, but a user can only be on 1 course. You can also reference all users on a particular course like:
course = Course.objects.get(name='course_name')
course_users = course.userprofile_set.all()
HTH
.
