Fleshed out the table storage service and started syncing logic

Habitica.Todoist.Integration.Model/Storage/Enums/TodoApp.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Habitica.Todoist.Integration.Model.Storage.Enum
+{
+    public enum TodoApp
+    {
+        Habitica = 1,
+        Todoist = 2
+    }
+}