Fix: Repository Monitor should detect changes

Disco.Data/Repository/DiscoDataContext.cs

@@ -73,6 +73,8 @@ namespace Disco.Data.Repository
         {
             int changeCount = 0;
 
+            this.ChangeTracker.DetectChanges();
+
             // Notify before changes are committed
             var changes = Monitor.RepositoryMonitor.BeforeSaveChanges(this);