Admin\Form\User\EditDefinition::define PHP Method

    public function define(Form $form)
    {
        parent::define($form);
        $form->wrap('created', null, function (Form $form) {
            $form->add('group', new RadioField())->label(Translator::translate('natika.user.field.group'))->set('class', 'btn-group')->addOption(new Option('Admin', 2))->addOption(new Option('Member', 1));
        });
    }