renamed class names to avoid conflicts

lib/data/methods/group.dart

@@ -1,7 +1,7 @@
 import 'package:game_tracker/data/database.dart';
 import 'package:drift/drift.dart';
 
-extension Group on AppDatabase {
+extension GroupMethods on AppDatabase {
   Future<List<GroupData>> getAllGroups() async {
     return await select(group).get();
   }

lib/data/methods/user.dart

@@ -1,7 +1,7 @@
 import 'package:game_tracker/data/database.dart';
 import 'package:drift/drift.dart';
 
-extension User on AppDatabase {
+extension UserMethods on AppDatabase {
   Future<List<UserData>> getAllUsers() async {
     return await select(user).get();
   }

lib/data/methods/user_group.dart

@@ -1,7 +1,7 @@
 import 'package:game_tracker/data/database.dart';
 import 'package:drift/drift.dart';
 
-extension UserGroup on AppDatabase {
+extension UserGroupMethods on AppDatabase {
   Future<List<UserGroupData>> getAllUsersAndGroups() async {
     return await select(userGroup).get();
   }