infrastructure for dealing with client cache invalidation in a multi-user environment

Oqtane.Server/Startup.cs

@@ -162,6 +162,7 @@ namespace Oqtane.Server
             // register singleton scoped core services
             services.AddSingleton<IConfigurationRoot>(Configuration);
             services.AddSingleton<IInstallationManager, InstallationManager>();
+            services.AddSingleton<ISyncManager, SyncManager>();
 
             // register transient scoped core services
             services.AddTransient<IModuleDefinitionRepository, ModuleDefinitionRepository>();