public function mainAction(Request $request)
{
    $user = $this->getUser();

    $form = $this->createForm(UserType::class, $user);

    $form->handleRequest($request);
    if ($form->isValid() && $form->isSubmitted()) {
        $password = $this->get('security.password_encoder')
            ->encodePassword($user, $user->getPlainPassword());
        $user->setPassword($password);
        $em = $this->getDoctrine()->getEntityManager();
        $em->persist($user);
        $em->flush();
    }

    return $this->render('AppBundle:uzduotis:index.html.twig', [
        'form' => $form->createView(),
        'user' => $user
    ]);
}

* @Route("/logout", name="logout")
 * @Method({"GET"})
 */
public function logoutAction(Request $request)
{
    $session = $this->$request->getSession();
    $session = $this->get('session')->clear();
    return $this->render('AppBundle:uzduotis:login.html.twig');
}