Laravel 5.2 binding session object to router

Im having a trouble binding a object in session to the router. This is in a fresh install of Laravel 5.2 and this is what i have:

So my routes file:

    Route::resource('carts', 'CartsController');

In RouteServiceProvider:

    public function map(Router $router)
{

    $router->group(['namespace' => $this->namespace], function ($router) {
        $router->bind('carts', function ($value) {
            return Cart::get($value);
        });
        require app_path('Http/routes.php');
    });
}

and this is in the Cart class:

    public static function get($cartId)
{
    if (\Session::has('carts.' . $cartId)) {
        $cart = \Session::get('carts.' . $cartId);
    } else {
        $cart = new Cart($cartId);
    }
    return $cart;
}

So untill this step Session is not loaded. I tried to starting session manually by calling \Session::start(); but then it wouldn't get the expected data even if there are cart object in session. I also tried dd(\Session::all()), but it returns an empty array.

Does anyone know when to bind a object to route so that the session is also loaded?

via Chebli Mohamed