refactor: modernized GenericRepository and UnitOfWork with newer code from Roma

Database/UnitOfWork/IUnitOfWork.cs

@@ -0,0 +1,16 @@
+
+namespace GamificationService.Database.UnitOfWork;
+
+public interface IUnitOfWork
+{
+    #region Repositories
+    #endregion
+
+    #region Methods
+    bool SaveChanges();
+    Task<bool> SaveChangesAsync();
+    Task BeginTransactionAsync();
+    Task CommitTransactionAsync();
+    Task RollbackTransactionAsync();
+    #endregion
+}

Database/UnitOfWork/UnitOfWork.cs

@@ -0,0 +1,68 @@
+using Microsoft.EntityFrameworkCore.Storage;
+
+namespace GamificationService.Database.UnitOfWork;
+
+public class UnitOfWork : IUnitOfWork
+{
+    #region Fields
+    private readonly ApplicationContext _context;
+    private IDbContextTransaction? _transaction;
+
+    #endregion
+
+    public UnitOfWork(ApplicationContext context)
+    {
+        _context = context;
+    }
+
+    #region Repositories
+    #endregion
+
+    #region Save Methods
+    public bool SaveChanges() => _context.SaveChanges() > 0;
+
+    public async Task<bool> SaveChangesAsync() => (await _context.SaveChangesAsync()) > 0;
+    #endregion
+
+    #region Transactions
+    public async Task BeginTransactionAsync()
+    {
+        if (_transaction is not null)
+            throw new InvalidOperationException("A transaction has already been started.");
+
+        _transaction = await _context.Database.BeginTransactionAsync();
+    }
+
+    public async Task CommitTransactionAsync()
+    {
+        if (_transaction is null)
+            throw new InvalidOperationException("A transaction has not been started.");
+
+        try
+        {
+            await _transaction.CommitAsync();
+        }
+        catch
+        {
+            await RollbackTransactionAsync();
+            throw;
+        }
+        finally
+        {
+            await _transaction.DisposeAsync();
+            _transaction = null;
+        }
+    }
+
+    public async Task RollbackTransactionAsync()
+    {
+        if (_transaction is null)
+            return;
+
+        await _transaction.RollbackAsync();
+        await _transaction.DisposeAsync();
+        _transaction = null;
+    }
+    #endregion
+    
+}