Added the possibility to convert a subtask to a task

app/Model/Subtask.php

@@ -397,4 +397,31 @@ class Subtask extends Base
             }
         });
     }
+
+    /**
+     * Convert a subtask to a task
+     *
+     * @access public
+     * @param  integer $project_id
+     * @param  integer $subtask_id
+     * @return integer
+     */
+    public function convertToTask($project_id, $subtask_id)
+    {
+        $subtask = $this->getById($subtask_id);
+
+        $task_id = $this->taskCreation->create(array(
+            'project_id' => $project_id,
+            'title' => $subtask['title'],
+            'time_estimated' => $subtask['time_estimated'],
+            'time_spent' => $subtask['time_spent'],
+            'owner_id' => $subtask['user_id'],
+        ));
+
+        if ($task_id !== false) {
+            $this->remove($subtask_id);
+        }
+
+        return $task_id;
+    }
 }