Added basic structure for game implementation

lib/data/dao/group_game_dao.dart

@@ -0,0 +1,33 @@
+import 'package:drift/drift.dart';
+import 'package:game_tracker/data/db/database.dart';
+import 'package:game_tracker/data/db/tables/group_game_table.dart';
+import 'package:game_tracker/data/dto/group.dart';
+
+part 'group_game_dao.g.dart';
+
+@DriftAccessor(tables: [GroupGameTable])
+class GroupGameDao extends DatabaseAccessor<AppDatabase>
+    with _$GroupGameDaoMixin {
+  GroupGameDao(super.db);
+
+  /// Checks if there is a group associated with the given [gameId].
+  /// Returns `true` if there is a group, otherwise `false`.
+  Future<bool> hasGameGroup(String gameId) async {
+    final count =
+        await (selectOnly(groupGameTable)
+              ..where(groupGameTable.gameId.equals(gameId))
+              ..addColumns([groupGameTable.groupId.count()]))
+            .map((row) => row.read(groupGameTable.groupId.count()))
+            .getSingle();
+    return (count ?? 0) > 0;
+  }
+
+  Future<Group> getGroupByGameId(String gameId) async {
+    final result = await (select(
+      groupGameTable,
+    )..where((g) => g.gameId.equals(gameId))).getSingle();
+
+    final group = await db.groupDao.getGroupById(result.groupId);
+    return group;
+  }
+}