bugfix: fix polls models.py users

djangoldp_polls/models.py

 from django.conf import settings
 from django.db import models
 from djangoldp.models import Model
-
-from django.contrib.auth import get_user_model
 from django.db.models import Sum
 
 from djangoldp_conversation.models import Conversation
 from djangoldp_circle.models import Circle
 
-User = get_user_model()
+User = settings.AUTH_USER_MODEL
 User.name=User.get_full_name