yii\rbac\DbManager::removeAllAssignments PHP Method

    public function removeAllAssignments()
    {
        $this->db->createCommand()->delete($this->assignmentTable)->execute();
    }

 public function actionRemoveAllAssignments()
 {
     if ($this->confirm('Are you sure want to remove all role assignments?')) {
         $this->_authManager->removeAllAssignments();
     }
     return 0;
 }