Laravel：从控制器重定向到特定的URL

I'm having troubles to just redirect to a url from a controller.

This is my trigger:

<form method="POST" action="{{ url('creategroup") }}">

Then, this is the catcher:

Route::post('/creategroup', 'GroupController@store');

And finally, this is my method:

public function store(Request $request) {
    /* bla bla bla */
    return Redirect::to('/users/'.$request->id.'/groups/');
}

But it doesn't work, the url just stops in localhost/creategroup and it shows a page that say that the page has expired, and it doesn't redirect to any place. Help please.