We can use Auth component in cakephp for authentication and authorization objects. Since it easy and secure way to do this.

Write following in your App controller

public $components = array(
            'Auth' => array('loginAction' => array('controller' => 'users', 'action' => 'login'),
                'logoutRedirect' => array('controller' => 'pages', 'action' => 'home'),
                'authError' => 'You don\'t have access here.',
            )
        );

Following in your User controller

//LOGIN

public function login() {
     if ($this->request->is('post')) {
        $this->Auth->authenticate = array(
            'Form' => array(
                'userModel' => 'TableName',//Employer,Athlete or etc 
            )
        );
        if ($this->Auth->login()) {
            $this->redirect(array('controller' => 'users', 'action' => 'profile'));
        } else {
            $this->Session->setFlash(__('Invalid username or password, try again'));
            $this->redirect(array('controller' => 'Pages', 'action' => 'home#toLogin'));
        }
    }
}

//LOGOUT

public function logout() {
    $this->Auth->autoRedirect = false;
    $this->Auth->logout();
    $this->redirect(array('controller' => 'pages', 'action' => 'home'));
}