Added createdAt attribute in dto classes and json schema

lib/data/dto/player.dart

@@ -3,8 +3,8 @@ import 'package:uuid/uuid.dart';
 
 class Player {
   final String id;
-  final String name;
   final DateTime createdAt;
+  final String name;
 
   Player({String? id, DateTime? createdAt, required this.name})
     : id = id ?? const Uuid().v4(),
@@ -18,8 +18,13 @@ class Player {
   /// Creates a Player instance from a JSON object.
   Player.fromJson(Map<String, dynamic> json)
     : id = json['id'],
+      createdAt = DateTime.parse(json['createdAt']),
       name = json['name'];
 
   /// Converts the Player instance to a JSON object.
-  Map<String, dynamic> toJson() => {'id': id, 'name': name};
+  Map<String, dynamic> toJson() => {
+    'id': id,
+    'createdAt': createdAt.toIso8601String(),
+    'name': name,
+  };
 }