OAuthBundle\Controller\OAuthController::disconnectServiceAction PHP Method

    public function disconnectServiceAction(Request $request, $service, $usernameId, $accessToken)
    {
        if ($request->isMethod('POST') && $this->isCsrfTokenValid('authenticate', $request->request->get('_csrf_token'))) {
            $em = $this->getDoctrine()->getManager();
            $user = $em->getRepository('AppBundle:User')->findOneBy(array($service . '_id' => $usernameId, $service . '_access_token' => $accessToken));
            if ($user && $user->getId() === $this->getUser()->getId()) {
                $user->setGithubId(null);
                $user->setGithubAccessToken(null);
                $em->persist($user);
                $em->flush();
            }
        }
        return $this->redirectToRoute('admin_index');
    }