public TodosController(
     TodoViewModelService viewModelService,
     UserManager <ApplicationUser> userManager,
     AzureBlobTodosClient blobClient,
     TodoRepository todoRepository,
     IHubContext <TodoHub> hubContext
     )
 {
     this.viewModelService = viewModelService;
     this.userManager      = userManager;
     this.hubContext       = hubContext;
     this.blobClient       = blobClient;
     this.todoRepository   = todoRepository;
 }
 public TodoViewModelService(AzureBlobTodosClient blobClient)
 {
     this.blobClient = blobClient;
 }