protected function bindRepositories()
    {
        $bindings = [
            AttributeRepositoryContract::class      => AttributeRepository::class,
            AttributeValueRepositoryContract::class => AttributeValueRepository::class,
            ProductRepositoryContract::class        => ProductRepository::class,
            ProductTypeRepositoryContract::class    => ProductTypeRepository::class,
        ];

        foreach ($bindings as $contract => $implementation) {
            $this->app->bind($contract, $implementation);
        }
    }