Flarum\Database\AbstractModel::boot PHP Method

    public static function boot()
    {
        parent::boot();
        static::saved(function (AbstractModel $model) {
            foreach ($model->releaseAfterSaveCallbacks() as $callback) {
                $callback($model);
            }
        });
        static::deleted(function (AbstractModel $model) {
            foreach ($model->releaseAfterDeleteCallbacks() as $callback) {
                $callback($model);
            }
        });
    }

 /**
  * Boot the model.
  *
  * @return void
  */
 public static function boot()
 {
     parent::boot();
     static::deleted(function (Group $group) {
         $group->raise(new GroupWasDeleted($group));
         $group->permissions()->delete();
     });
 }