Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /var/www/html/prod/vendor/zxbodya/yii2-gallery-manager/migrations/m140930_003227_gallery_manager.php:7 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/zxbodya/yii2-gallery-manager/migrations/m140930_003227_gallery_manager.php on line 7