Controller cleanup (#30)

* Cleaning up routes.

* Adding signout functionality

* Added simple checkout behavior

src/Web/Interfaces/IBasketService.cs

@@ -10,5 +10,7 @@ namespace ApplicationCore.Interfaces
         Task<BasketViewModel> CreateBasketForUser(string userId);
 
         Task AddItemToBasket(int basketId, int catalogItemId, decimal price, int quantity);
+
+        Task Checkout(int basketId);
     }
 }