MIGRATIONS: fixed (and replaced) the previous migrations.

dav_registration/models.py

@@ -22,7 +22,6 @@ one_day = datetime.timedelta(1)
 
 @python_2_unicode_compatible
 class Registration(models.Model):
-    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
     event = models.ForeignKey(Event, related_name='registrations')
     created_at = models.DateTimeField(auto_now_add=True)