title: Could not resolve URL for hyperlinked relationship using view name "itemimages-detail"
body: <p><br>
  I used to have a one picture field and I wanted to change it to multiple pictures field:
  I had </p>
  
  <pre><code>picture = models.ImageField(null=True, blank=True, upload_to="items")
  </code></pre>
  
  <p>So I created a new model : </p>
  
  <pre><code>class ItemImages(models.Model):
      itemImage = models.ForeignKey(Item, related_name='pictures')
      image = models.ImageField(null=True, blank=True, upload_to="items")
  </code></pre>
  
  <p>Afterwards, I created the viewset: (<strong>Please note that I don't know what I'm doing</strong>)</p>
  
  <pre><code>class ItemImagesViewSet(viewsets.GenericViewSet):
      for_model = Item
      queryset = Item.objects.all()
      serializer_class = ItemImagesSerializer
      permission_classes = (permissions.IsAuthenticated, IsOwnerOrReadOnly)
  </code></pre>
  
  <p>Then the urls turn : </p>
  
  <pre><code>router = ExtendedSimpleRouter()
  ...
  (
      router.register(r'items', ItemViewSet)
            .register(r'itemimages', ItemImagesViewSet, 'items-images', parents_query_lookups=['items']) # I added this line 
            .register(r'reviews',
                      ItemReviewViewSet,
                      'items-review',
                      parents_query_lookups=['content_id'])
  )
  </code></pre>
  
  <p>My serializers : </p>
  
  <pre><code>from rest_framework import serializers
  from django.utils.translation import ugettext_lazy as _
  
  from inventory.models import Item, ItemImages
  from users.api.serializers import ObjectReviewsSerializer
  
  
  class ItemSerializer(ObjectReviewsSerializer):
      class Meta:
          model = Item
          fields = (
              'category', 'id', 'pictures', 'created', 'title',
              'url', 'value', 'user', 'reviews_url', 'rating', 'description'
          )
          read_only_fields = ('user', 'created', 'modified', '')
  
      def create(self, validated_data):
          validated_data.update({
              'user': self.context['request'].user,
          })
          return super(ItemSerializer, self).create(validated_data)
  
      def validate(self, attrs):
          more_fee = attrs.get('more_fee', None)
          less_fee = attrs.get('less_fee', None)
          if not more_fee and not less_time_fee and not self.instance:
              msg = _('You should provide either a more fee or a less  fee')
              raise serializers.ValidationError(msg)
          return attrs
  
  
  class ItemImagesSerializer(ObjectReviewsSerializer):
      class Meta:
          model = ItemImages
  </code></pre>
  
  <p>It gives the error stated in title when I'm requesting <code>/items/23</code>
  I know I'm doing a lot of things wrongly but I fail to know what and why.<br>
  I'm new to Django Rest and Django in general and I'm playing with an existent project (trying to change one picture to many)</p>
  
  <p>Complete error message: </p>
  
  <blockquote>
    <p>ImproperlyConfigured at /api/v1/items/23/ Could not resolve URL for
    hyperlinked relationship using view name "itemimages-detail". You may
    have failed to include the related model in your API, or incorrectly
    configured the <code>lookup_field</code> attribute on this field.</p>
  </blockquote>