我使用node.js和express和sequelize，我的数据库是mysql。我尝试创建一个类模型，如文档中所写：https://sequelize.org/master/manual/model-basics.html。我可以连接到数据库，但不知道如何同步模型与数据库，以创建表。以下是我的用户模型：

const { DataTypes, Model } = require('sequelize');
const connection = require("../server");

export class User extends Model { }

User.init({
    id: {
        type: DataTypes.BIGINT,
        autoIncrement: true,
        primaryKey: true,
        unique: true,
        allowNull: false
    },
    username: {
        type: DataTypes.STRING,
        allowNull: false,
        unique: true,
    },
    password: {
        type: DataTypes.STRING,
        allowNull: false,
    },
    userType: {
        type: DataTypes.STRING,
        allowNull: false,
    }
}, {
    connection
});

这是我的服务器js：

const express = require("express");
const Sequelize = require("sequelize");

const app = express();
const port = 8080;

const connection = new Sequelize("coupons2", "root", "1234", {
    host: "localhost",
    dialect: "mysql"
})

connection.sync()
    .then(() => {
        console.log("Connection to DB was successful");
    })
    .catch(err => {
        console.error("Unable to connect to DB", err);
    });

app.listen(port, () => {
    console.log(`Server is running on port ${port}`);
})

module.exports = connection;

谢谢大家!