Backend - Fix Response DTOs (PurchaseItem)

[liangricky7]

Fix Response DTOs (PurchaseItem)

Your task is to now diversify your ResponseDTOs. Currently, you only have one singular ResponseDTO that just returns all data of a resource. This was intentionally assigned by me so y'all could learn the other stuff of backend first, but it is now time to make correct Response DTOs.

Creating new Response DTOs

When creating your Response DTOs, consider why your service method is being called and where. How much information is the user expecting to see whenever they perform an action? Think of the grand scope of things.

Recall our How to Backend Slides: https://docs.google.com/presentation/d/1zIsSjI_YJa7hcsjNSL8SHdBNZ-Fk_fXLXEdvYz-lw6I/edit?slide=id.g38a016d32e5_0_100#slide=id.g38a016d32e5_0_100

If you do not understand the scope of where your resource lies and cannot imagine what the user would want from taking the respective action of your service method, let me know!