Create models and Clean Arch boilerplate

CSR.Infrastructure/Persistence/User.cs

@@ -0,0 +1,17 @@
+namespace CSR.Infrastructure.Persistence;
+
+public class User
+{
+  public int Id { get; set; }
+  public required string Username { get; set; }
+  public required string Email { get; set; }
+  public required string PasswordHash { get; set; }
+  public required int RoleId { get; set; }
+
+  // Navigation property
+  public Role Role { get; set; } = null!;
+
+  // prevent direct instantiation
+  // use UserService to create a new user
+  internal User() { }
+}