ADD: addKeyword function for add keyword to database

if user is not exist in database, create user
if keyword is not exist in database, create keyword

+let database = module.exports = {};
+
+const db = require("../models")
+const User = db.user
+const Keyword = db.keyword
+const UserKeyword = db.userKeyword
+
+
+database.addKeyword = async function(keyword, userId) {
+
+    const u = await User.findOrCreate({
+        where: {
+            userId: userId
+        }
+    })
+
+    const k = await Keyword.findOrCreate({
+        where: {
+            keyword: keyword
+        }
+    })
+
+    await UserKeyword.findOrCreate({
+        where: {
+            userId: u[0].id,
+            keywordId: k[0].id
+        }
+    })
+}

@@ -4,11 +4,13 @@ const setFlexMessage = require("./apis/setFlexMessage");
 const fs = require("fs");
 
 const { sequelize } = require('./models')
+const database = require("./apis/database");
 
 // Initialize DB connection
 sequelize.sync({ force: false })
     .then(() => {
         console.log('database connection complete');
+        database.addKeyword("rtx3080", "phobyjun")
     })
     .catch((err) => {
         console.log('database connection failed');

@@ -36,8 +36,9 @@ db.Sequelize = Sequelize;
 
 db.user = require("./user")(sequelize, Sequelize);
 db.keyword = require("./keyword")(sequelize, Sequelize);
+db.userKeyword = sequelize.define('user_keywords');
 
-db.user.belongsToMany(db.keyword, {through: 'user_keyword'});
-db.keyword.belongsToMany(db.user, {through: 'user_keyword'});
+db.user.belongsToMany(db.keyword, {through: db.userKeyword});
+db.keyword.belongsToMany(db.user, {through: db.userKeyword});
 
 module.exports = db;

@@ -7,7 +7,7 @@ module.exports = (sequelize, DataTypes) => {
             primaryKey: true
         },
         userId: {
-            type: DataTypes.INTEGER,
+            type: DataTypes.STRING,
             allowNull: false
         }
     })