title: Extending django.contrib.auth.models.User model with custom fields in Django
body: <p>I'm using Django 1.8.2 with python 2.7.3, rest framework and allauth. I'm trying to extend django.contrib.auth.models.User for adding custom fields, but the returned json is empty and there are Users created:</p>
  
  <p><strong>In models.py</strong></p>
  
  <pre><code>from django.contrib.auth.models import User
  from django.db import models
  
  class MyUser(models.Model):
      user = models.OneToOneField(User)
      black_coffee = models.IntegerField(default=0)
      coffee_with_milk = models.IntegerField(default=0)
      coffee_cut = models.IntegerField(default=0)
  </code></pre>
  
  <p><strong>In serializers.py</strong></p>
  
  <pre><code>from rest_framework import serializers
  from cafeterias.models import MyUser
  
  class UserSerializer(serializers.HyperlinkedModelSerializer):
      # snippets = serializers.HyperlinkedRelatedField(many=True, view_name='snippet-detail', read_only=True)
  
      class Meta:
          model = MyUser
          fields = ('username', 'black_coffee', 'coffee_with_milk', 'coffee_cut')
  </code></pre>
  
  <p><strong>In views.py</strong></p>
  
  <pre><code>from cafeterias.models import MyUser
  from rest_framework import permissions
  from rest_framework import viewsets
  
  class UserViewSet(viewsets.ReadOnlyModelViewSet):
      queryset = MyUser.objects.all()
      serializer_class = UserSerializer
      permission_classes = (permissions.AllowAny,
                            IsOwnerOrReadOnly,)
  </code></pre>
  
  <p>Here is the result of the json:</p>
  
  <p>HTTP 200 OK
  Content-Type: application/json
  Vary: Accept
  Allow: GET, HEAD, OPTIONS</p>
  
  <p>{
      "count": 0,
      "next": null,
      "previous": null,
      "results": []
  }</p>