refactor(backend): update directory structure for models

packages/backend/src/models/util/id.ts

@@ -0,0 +1,9 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and other misskey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export const id = () => ({
+	type: 'varchar' as const,
+	length: 32,
+});