重构后端，改为 node 技术栈

backend/src/models/Brand.js

@@ -0,0 +1,22 @@
+const { DataTypes } = require('sequelize');
+const sequelize = require('../config/database');
+
+const Brand = sequelize.define('Brand', {
+  id: {
+    type: DataTypes.INTEGER,
+    primaryKey: true,
+    autoIncrement: true,
+    comment: '品牌 ID',
+  },
+  name: {
+    type: DataTypes.STRING(100),
+    unique: true,
+    allowNull: false,
+    comment: '品牌名称',
+  },
+}, {
+  tableName: 'brand',
+  comment: '耳机品牌',
+});
+
+module.exports = Brand;