Add project files.

OemanTrader.WPF/ViewModels/ViewModelBase.cs

@@ -0,0 +1,13 @@
+using OemanTrader.WPF.Models;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace OemanTrader.WPF.ViewModels
+{
+    public class ViewModelBase : ObservableObject
+    {
+    }
+}