public AllTransactionsViewModel(YnabApi.YnabApi ynabApi, ISessionStateService sessionStateService)
        {
            this._ynabApi = ynabApi;
            this._sessionStateService = sessionStateService;

            this.Transactions = new BindableCollection<TransactionsByMonth>();
        }
        public AddTransactionViewModel(YnabApi.YnabApi api, ISavvyNavigationService navigationService, ILoadingService loadingService, ISessionStateService sessionStateService)
        {
            this._api = api;
            this._navigationService = navigationService;
            this._loadingService = loadingService;
            this._sessionStateService = sessionStateService;

            this.Payees = new BindableCollection<Payee>();
            this.Accounts = new BindableCollection<Account>();
            this.Categories = new BindableCollection<CategoryViewModel>();

            this.IsOutflow = true;
        }
        public static async Task<YnabApi.YnabApi> RegisterYnabApiAsync(this WinRTContainer container)
        {
            var sessionStateService = container.GetInstance<ISessionStateService>();

            var rootFolder = await ApplicationData.Current.LocalFolder.CreateFolderAsync("Dropbox", CreationCollisionOption.OpenIfExists);
            
            var fileSystem = new HybridFileSystem(rootFolder, sessionStateService);
            var api = new YnabApi.YnabApi(new YnabApiSettings(fileSystem, "Savvy", "Windows 10 Universal"));

            container.Instance(fileSystem);
            container.Instance(api);

            return api;
        }