public function boot()
 {
     if (!file_exists(resource_path('i18n'))) {
         mkdir(resource_path('i18n'), 0755);
     }
     I18n::$dir = resource_path('i18n');
     I18n::$locale = env('I18N');
     \Blade::directive('lang', function ($expression) {
         return "<?php echo __{$expression}; ?>";
     });
 }