add function to apply mutations over grpc

cmd/cart/pool-server.go

@@ -792,7 +792,18 @@ func (s *PoolServer) Serve(mux *http.ServeMux) {
 				http.Error(w, "Invalid HMAC", http.StatusUnauthorized)
 				return
 			} else {
+
+				cartId, ok := cart.ParseCartId(notification.OriginalReference)
 				log.Printf("Recieved notification event code: %s, %v", notification.EventCode, notification)
+				if ok {
+					host, ok := s.OwnerHost(uint64(cartId))
+					if ok {
+						log.Printf("Not owner of %d, owner: %s", cartId, host.Name())
+						//host.Apply(r.Context(), cartId)
+					} else {
+						log.Printf("I'm the owner of %d", cartId)
+					}
+				}
 			}
 		}
 		w.WriteHeader(http.StatusAccepted)