First commit that builds.

code/MessengerBroker.Db/Model/Sync.cs

@@ -0,0 +1,15 @@
+namespace MessengerBroker.Db.Model
+{
+    public class Sync
+    {
+        public int Id { get; set; }
+
+        public Guid BrokerId { get; set; }
+
+        public DateTime StartedUtc { get; set; }
+
+        public DateTime? FinishedUtc { get; set; }
+
+        public long? Changes { get; set; }
+    }
+}