protected function createClient()
    {
        $this->client = new OAuthServer([
            'identifier' => Configuration::get('key'),
            'secret' => Configuration::get('secret'),
            'callback_uri' => Configuration::get('callbackUrl'),
            'name' => Configuration::get('name'),
            'expiration' => Configuration::get('expiration'),
            'scope' => Configuration::get('scope'),
        ]);

        return $this;
    }