fix wrong event id

handlers/events.go

@@ -57,7 +57,7 @@ func (dh *DatabaseHandler) AddAttendeesToEvent(newEvent models.Event) error {
 	}
 
 	var event models.Event
-	err := dh.database.GetById(&event, uint(event.Id))
+	err := dh.database.GetById(&event, uint(newEvent.Id))
 	if err != nil {
 		return err
 	}