change order of hook invocation and setting task id (#3339)

this prevents that the task id is always returned as zero after a hook
is run on it
closes #3312

src/TDB2.cpp

@@ -118,12 +118,13 @@ void TDB2::add (Task& task)
   // update the cached working set with the new information
   _working_set = std::make_optional (std::move (ws));
 
+  // run hooks for this new task
+  Context::getContext ().hooks.onAdd (task);
+
   if (id.has_value ()) {
       task.id = id.value();
   }
 
-  // run hooks for this new task
-  Context::getContext ().hooks.onAdd (task);
 }
 
 ////////////////////////////////////////////////////////////////////////////////