public function onRoleCreateOrEdit(Model $model = null)
    {
        $this->onList();
        Breadcrumbs::register('edit-role', function($breadcrumbs) use($model) {
            $breadcrumbs->parent('roles-list');
            $exists = is_null($model) ? false : $model->exists;
            $name   = ($exists) ? 'Edit Group ' . $model->full_name : 'Add Group';
            $breadcrumbs->push($name, '#');
        });
        view()->share('breadcrumbs', Breadcrumbs::render('edit-role'));
    }