add feat upload pbg task

app/Models/PbgTask.php

@@ -46,4 +46,8 @@ class PbgTask extends Model
     {
         return $this->hasMany(TaskAssignment::class, 'pbg_task_uid', 'uuid');
     }
+
+    public function attachments(){
+        return $this->hasMany(PbgTaskAttachment::class, 'pbg_task_id', 'id');
+    }
 }