FatController.php

<?php
namespace Acme\DemoBundle\Controller;

class FatController extends Controller
{
    /**
     * @Route("/{id}/edit", name="some_edit_route")
     * @Method({"GET"})
     * @Template()
     */
    public function editAction($id)
    {
        $model = $this->loadModel($id);
        $form = $this->createForm('some_type', $model);

        return array('form' => $form);
    }

    /**
     * @Route("/{id}/edit", name="some_update_route")
     * @Method({"POST"})
     * @Template("AcmeDemoBundle:FatController:edit.html.twig")
     */
    public function updateAction(Request $request, $id)
    {
        $model = $this->loadModel($id);
        $form = $this->createForm('some_type', $model);

        $form->bind($request);

        if ($form->isValid()) {
            // updating stuff here ...

            return $this->redirect($this->generateUrl('some_edit_route', array('id' => $id)));
        }

        return array('model' => $model);
    }

}