public static void SaveRetailer(this ISettingsService settingsService, Retailer retailer)
{
settingsService.AddOrUpdateAppSettings(CFG_RETAILER_ID, retailer.Id.ToString());
settingsService.AddOrUpdateAppSettings(CFG_RETAILER_NAME, retailer.Name);
settingsService.AddOrUpdateAppSettings(CFG_RETAILER_LONGITUDE, retailer.Longitude.ToString());
settingsService.AddOrUpdateAppSettings(CFG_RETAILER_LATITUDE, retailer.Latitude.ToString());
}