private static XdbModel BuildModel()
        {
            XdbModelBuilder modelBuilder = new XdbModelBuilder("PushSubscriptionsModel", new XdbModelVersion(1, 0));

            // Facets and events here
            modelBuilder.RegisterType <PushSubscription>(true);
            modelBuilder.DefineFacet <Contact, PushSubscriptions>(FacetNames.PushSubscriptions);

            return(modelBuilder.BuildModel());
        }