create and update dao's

lib/data/dao/user_group_dao.dart

@@ -0,0 +1,33 @@
+import 'package:game_tracker/data/database.dart';
+import 'package:drift/drift.dart';
+
+extension UserGroupDao on AppDatabase {
+  Future<List<UserGroupTableData>> getAllUsersAndGroups() async {
+    return await select(userGroupTable).get();
+  }
+
+  Future<List<UserGroupTableData>> getUsersGroups(String userId) async {
+    return await (select(
+      userGroupTable,
+    )..where((uG) => uG.userId.equals(userId))).get();
+  }
+
+  Future<List<UserGroupTableData>> getGroupsUsers(String groupId) async {
+    return await (select(
+      userGroupTable,
+    )..where((uG) => uG.groupId.equals(groupId))).get();
+  }
+
+  Future<void> addUserToGroup(String userId, String groupId) async {
+    await into(
+      userGroupTable,
+    ).insert(UserGroupTableCompanion.insert(userId: userId, groupId: groupId));
+  }
+
+  Future<void> removeUserFromGroup(String userId, String groupId) async {
+    await (delete(
+          userGroupTable,
+        )..where((uG) => uG.userId.equals(userId) & uG.groupId.equals(groupId)))
+        .go();
+  }
+}