Add more logging

cmd/hubserver/handler.go

@@ -176,7 +176,9 @@ func (handler *subscriptionHandler) handleSubscription(w http.ResponseWriter, r
 		if validateURL(validationURL.String(), ourChallenge) {
 			log.Printf("subscribe: validation valid\n")
 			err = handler.store.Subscribe(topicURL.String(), storage.Subscriber{callbackURL.String(), leaseSeconds, secret, time.Now()})
+			if err != nil {
 				log.Printf("saving suscriber failed: %v", err)
+			}
 		} else {
 			log.Printf("subscribe: validation failed\n")
 		}
@@ -186,6 +188,7 @@ func (handler *subscriptionHandler) handleSubscription(w http.ResponseWriter, r
 }
 
 func validateURL(url, challenge string) bool {
+	log.Println("validateURL: ", url)
 	client := http.Client{}
 
 	req, err := http.NewRequest(http.MethodGet, url, nil)