Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /var/www/html/vendor/yiisoft/yii2/i18n/migrations/m150207_210500_i18n_init.php:19 Stack trace: #0 {main} thrown in /var/www/html/vendor/yiisoft/yii2/i18n/migrations/m150207_210500_i18n_init.php on line 19