Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /var/www/html/prod/vendor/yiisoft/yii2/rbac/migrations/m180523_151638_rbac_updates_indexes_without_prefix.php:20 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/yiisoft/yii2/rbac/migrations/m180523_151638_rbac_updates_indexes_without_prefix.php on line 20