adding draft subtask logic to backend

be/app/Http/Resources/SubTaskResource.php

@@ -17,6 +17,7 @@ class SubTaskResource extends JsonResource
     {
         return [
             'id'                      => $this->id,
+            'is_draft'                => $this->is_draft,
             'type'                    => $this->type,
             'created_by'              => $this->created_by,
             'master_task'             => $this->mastertask->title,