Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /users/quirl/www/filemanager/spark/protected/runtime/module_backups/calendar_1736926948/migrations/m170717_205750_participant_info.php:11 Stack trace: #0 {main} thrown in /users/quirl/www/filemanager/spark/protected/runtime/module_backups/calendar_1736926948/migrations/m170717_205750_participant_info.php on line 11