no message

be/app/Observers/MasterTaskObserver.php

@@ -10,4 +10,10 @@ class MasterTaskObserver
     {
         $mastertask->color = MasterTask::generateMasterTaskColor();
     }
+
+    public function updating(MasterTask $mastertask)
+    {
+        // to prevent updating created_by field. this field cannot be updated once created.
+        $mastertask->created_by = $mastertask->getOriginal('created_by');
+    }
 }