add possibility to insert data on an API - call

add an array_merge to the data - variable to insert additional data.

Example:
```php
public function afterSave(\CakeEvent $event) {
	parent::afterSave($event);
	if ($event->subject->success) {
		$data['redirect_url'] = Router::url(array('controller' => 'quizzes', 'action' => 'thank_you'));
		$event->subject->controller->set(compact('data'));
	}
}
```