title: @detail_route does not work pagination in django rest framework
body: <p>Can I use @detail_router's pagination?</p>
  
  <pre><code>class GroupViewSet(viewsets.ReadOnlyModelViewSet):
      """
      Group View Set
      """
      queryset = Group.objects.all()
      serializer_class = GroupSerializer
      pagination_class = StandardResultsSetPagination
  
      @detail_route()
      def user(self, request, pk=None):
          _group = self.get_object()
          users_post = _group.user_set.all()
          page = self.paginate_queryset(users_post)
          if page is not None:
              serializers = UserSerializer(users_post, many=True, context={'request': request})
              return self.get_paginated_response(serializers.data)
          serializers = UserSerializer(users_post, many=True, context={'request': request})
          return Response(serializers.data)
  </code></pre>
  
  <p>Pagination does not work well in Djagno Rest Framework.</p>
  
  <p><a href="https://i.stack.imgur.com/gaq9A.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gaq9A.png" alt="enter image description here"></a></p>
  
  <p>It only works page size. One page has whole contents, and next page is same whole contents.
  How can I do for pagination?</p>