IndexerType added, this will store the source indexer in history, so users can see (if they care) and we can add an icon if we want.

NzbDrone.Core/Model/IndexerType.cs

@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace NzbDrone.Core.Model
+{
+    public enum IndexerType
+    {
+        Other = 0,
+        NzbsOrg = 1,
+        NzbMatrix = 2,
+        NzbsRus = 3,
+        Newzbin = 4
+    }
+}