public static void RegisterComponents()
        {
            var container = new UnityContainer();

            // register all your components with the container here
            // it is NOT necessary to register your controllers

            // without DbContextFactory
            container.RegisterType <DbContext, OrderContext>(new TransientLifetimeManager());
            container.RegisterType <IOrderRepository, OrderRepository>("NoFactory", new TransientLifetimeManager());

            // with DbContextFactory
            container.AddDbContextFactory <OrderContext>();
            container.RegisterType <IOrderRepository, OrderRepositoryWithFactory>("WithFactory", new TransientLifetimeManager());

            GlobalConfiguration.Configuration.DependencyResolver = new UnityDependencyResolver(container);
        }