use custom user model

Author: matclayton

experiments/models.py

@@ -1,4 +1,3 @@
-from django.contrib.auth.models import User
 from django.core.urlresolvers import reverse
 from django.db import models
 from django.core.serializers.json import DjangoJSONEncoder
@@ -166,7 +165,7 @@ def delete(self, *args, **kwargs):
 
 class Enrollment(models.Model):
     """ A participant in a split testing experiment """
-    user = models.ForeignKey(User, null=True)
+    user = models.ForeignKey(settings.AUTH_USER_MODEL, null=True)
     experiment = models.ForeignKey(Experiment)
     enrollment_date = models.DateTimeField(auto_now_add=True)
     last_seen = models.DateTimeField(null=True)