Diagram example of code in Layers:
+--------------------+
| Client |
| (Browser/Postman) |
+--------------------+
|
v
+--------------------+
| Controller Layer |
| Handles HTTP |
| requests/responses |
+--------------------+
|
v
+--------------------+
| Service Layer |
| Business Logic |
| Orchestrates tasks |
+--------------------+
|
v
+--------------------+
| Model Layer | <-- Represents entities like `User`
| Maps to Database |
+--------------------+
|
v
+--------------------+
| Repository Layer |
| Database Access |
| (CRUD Operations) |
+--------------------+
|
v
+--------------------+
| Database Layer |
| (PostgreSQL) |
+--------------------+
App includes CRUD Operations for: Registration | Authentication | Authorization