fix: Add @Id annotation to Problem record id field

[Rohit-code07]

Fix: Add Missing @Id Annotation in Problem Record

Issue Description

The Problem record in problems-service was missing the @Id annotation on its id field. Since Spring Data relies on @Id to identify the primary key, the absence of this annotation could prevent proper entity identification and affect repository operations.

Root Cause

Unlike UserProblem, which correctly defines the identifier field using @Id, the Problem record did not explicitly mark its primary key.

Before Fix

public record Problem(
    int id,
    String title,
    String acceptance,
    String difficulty
) {}

In this implementation, Spring Data cannot explicitly identify the primary key field.

Changes Made

Added the missing @Id annotation to the id field in Problem.java.

After Fix

import org.springframework.data.annotation.Id;

public record Problem(
    @Id int id,
    String title,
    String acceptance,
    String difficulty
) {}

Impact

• Enables Spring Data to correctly recognize the primary key field
• Improves repository behavior for operations such as findById()
• Ensures consistent entity mapping and avoids unexpected behavior in future database operations

Files Modified

problems-service/src/main/java/com/hardik/problemsservice/model/Problem.java

Related Issue

Fixes #130

[Rohit-code07]

Hi @hardikxk, I have resolved the issue and submitted a PR for it. Kindly review it and merge if everything looks good. Thank you!