Fatal error: Uncaught Error: Class "Illuminate\Database\Eloquent\Relations\Relation" not found in /var/www/html/usophy/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php:17 Stack trace: #0 {main} thrown in /var/www/html/usophy/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Relations/BelongsToMany.php on line 17