/// <summary>
        /// LoadBilleterAsync loader data fra vores database tabel "Billeter".
        /// </summary>

        public async void LoadBilleterAsync()
        {
            var billeter = await PersistencyService.LoadBilleterFromJsonAsync();

            if (billeter != null)
            {
                foreach (var b in Billeter)
                {
                    Billeter.Add(b);
                }
            }
            else
            {
                //Data til testformål
                Billeter.Add(new Billet(1, 123456789, 123456789, 123456789, new DateTime(2015, 05, 14), 1234, false));
                Billeter.Add(new Billet(2, 123456789, 123456789, 123456789, new DateTime(2015, 05, 14), 1234, false));
            }
        }