Implemented basic structure

lib/data/db/tables/group_table.dart

@@ -0,0 +1,9 @@
+import 'package:drift/drift.dart';
+
+class GroupTable extends Table {
+  TextColumn get id => text()();
+  TextColumn get name => text()();
+
+  @override
+  Set<Column<Object>> get primaryKey => {id};
+}

lib/data/db/tables/player_group_table.dart

@@ -0,0 +1,11 @@
+import 'package:drift/drift.dart';
+import 'package:game_tracker/data/methods/db/tables/group_table.dart';
+import 'package:game_tracker/data/methods/db/tables/user_table.dart';
+
+class PlayerGroupTable extends Table {
+  TextColumn get userId => text().references(UserTable, #id)();
+  TextColumn get groupId => text().references(GroupTable, #id)();
+
+  @override
+  Set<Column<Object>> get primaryKey => {userId, groupId};
+}

lib/data/db/tables/player_table.dart

@@ -0,0 +1,9 @@
+import 'package:drift/drift.dart';
+
+class PlayerTable extends Table {
+  TextColumn get id => text()();
+  TextColumn get name => text()();
+
+  @override
+  Set<Column<Object>> get primaryKey => {id};
+}