private async Task LogougAsync()
{
UserInformation.User = null;
var appSettingsService = new AppSettingsService();
var azureService = DependencyService.Get <IAzureService>();
appSettingsService.Remove(AuthenticaitonTokenKey);
appSettingsService.Remove(UserIdKey);
await azureService.GetMobileServicesClinet().LogoutAsync();
await LoginAsync(appSettingsService, azureService);
}