linking user with cart now also links user with nutritionist

authentication/views.py

@@ -42,6 +42,7 @@ class LinkDataViewSet(viewsets.ViewSet):
             return Response({'message': 'Cart is not found.'}, status=status.HTTP_400_BAD_REQUEST)
 
         user.diet_profile = diet_profile
+        user.nutritionist = cart.nutritionist
         user.save()
 
         cart.user = user