public function boot()
 {
     parent::boot();
     Models\Asset::observe(CreationLogObserver::class);
     Models\AssetVersion::observe(CreationLogObserver::class);
     Models\Page::observe(CreationLogObserver::class);
     Models\PageVersion::observe(CreationLogObserver::class);
     Models\Asset::observe(SetSiteObserver::class);
     Models\Group::observe(SetSiteObserver::class);
     Models\Page::observe(SetSiteObserver::class);
     Models\Tag::observe(SetSiteObserver::class);
     Models\URL::observe(SetSiteObserver::class);
     Models\Page::observe(DeletionLogObserver::class);
 }