Add base_manager_name param to User Meta

apps/user/models.py

@@ -62,8 +62,11 @@ class User(AbstractUser):
     USERNAME_FIELD = 'email'
     REQUIRED_FIELDS = ['username']
 
+    non_polymorphic = models.Manager()
+
     class Meta(AbstractUser.Meta):
         ordering = ('-date_joined',)
+        base_manager_name = 'non_polymorphic'
 
     def serialized(self):
         user_data = serializers.user.UserSerializer(instance=self).data