Fatal error: Uncaught Error: Class "yii\db\Migration" not found in /var/www/html/prod/vendor/yiisoft/yii2/web/migrations/m160313_153426_session_init.php:16 Stack trace: #0 {main} thrown in /var/www/html/prod/vendor/yiisoft/yii2/web/migrations/m160313_153426_session_init.php on line 16