public function register()
{
$this->app->singleton('onesignal', function ($app) {
$settings = $app['config']->get('services.onesignal');
$config = new Config();
$config->setApplicationId($settings['app_id']);
$config->setApplicationAuthKey($settings['app_key']);
$config->setUserAuthKey($settings['user_key']);
return new OneSignal($config);
});
}