activations_controller.php

function add() {
	if (!empty($this->data)) {
		$user = $this->User->find('first', array('conditions' => array('User.activation_token' => $this->data['User']['activation_token'])));
		if($user) {
			$this->data['User']['activated'] = '-!NOW()';
			$this->data['User']['activation_token'] = '-!NULL';
			$this->User->id = $user['User']['id'];
		}
		$this->User->save($this->data);
	}
}