title: Multiple lookup_fields for django rest framework
body: <p>I have multiple API which historically work using <code>id</code> as the lookup field:</p>
  <pre><code>/api/organization/10
  </code></pre>
  <p>I have a frontend consuming those api.</p>
  <p>I'm building a new interface and for some reasons, I would like to use a slug instead an id:</p>
  <pre><code>/api/organization/my-orga
  </code></pre>
  <p>The API is built with Django Rest Framework. Except the change of lookup field, the api behavior should stay the same.</p>
  <p>Is there a solution to allow my API to work with both a <code>slug</code> and a <code>pk</code> ? Those two path should give them same results:</p>
  <pre><code>/api/organization/10
  /api/organization/my-orga
  </code></pre>
  <p>Here is my API definition:</p>
  <pre><code># urls.py
  router = DefaultRouter()
  router.register(r'organization', Organization)
  urlpatterns = router.urls
  
  #view.py
  class Organization(viewsets.ModelViewSet):
      queryset = OrganisationGroup.objects.all()
      serializer_class = OrganizationSerializer
  
  # serializer.py
  class OrganizationSerializer(PermissionsSerializer):
      class Meta:
          model = Organization
  </code></pre>