mengapa Call to undefined method Illuminate\Database\Query\Builder::add() muncul

Call to undefined method Illuminate\Database\Query\Builder::add() muncul saat saya update composer .dalam composer saya memberikan "khill/lavacharts": "2.5.*", "gloudemans/shoppingcart": "dev-master" dan di app.php Khill\Lavacharts\Laravel\LavachartsServiceProvider::class, Gloudemans\Shoppingcart\ShoppingcartServiceProvider::class, 'Cart' => Gloudemans\Shoppingcart\Facades\Cart::class,

dan pada controllernya seperti ini: public function cart($id){ $productcart=Product::find($id); $id = $productcart ->id; $name = $productcart ->name; $qty = 1; $price = $productcart ->price;

$data = [ 'id' => $id, 'name' =>$name, 'qty' => $qty, 'price' => $price, 'options' => ['size'=>'large'] ]; Cart::add($data); $cart_product=Cart::Product(1); Return view::make('productcart')->with('cart_product',$cart_product); }

apa yang harus dilakukan agar error itu tidak muncul , mohon bantuannya ??