replace express into koa

 const lineCtrl = require("./line.ctrl");
 const lineCtrl = require("./line.ctrl");
 
 
 
 
-var express = require('express');
+var Koa = require('koa');
 const request = require('request');
 const request = require('request');
 const TARGET_URL = 'https://api.line.me/v2/bot/message/reply'
 const TARGET_URL = 'https://api.line.me/v2/bot/message/reply'
 const TOKEN = 'tdN03DyXDAcKGZsuiPndaU7UC2GzuEQYUhPCkDnGWXGGdiPmV15QYbFU1U5JP5EpiETIKLqOmci/RxFZTfD7FRMED0OpT+3qgEYBNf8T9/jRzHRm7rblBLtzFBVOeXeYRcluOsz4koE4JaAJaUtMtwdB04t89/1O/w1cDnyilFU='
 const TOKEN = 'tdN03DyXDAcKGZsuiPndaU7UC2GzuEQYUhPCkDnGWXGGdiPmV15QYbFU1U5JP5EpiETIKLqOmci/RxFZTfD7FRMED0OpT+3qgEYBNf8T9/jRzHRm7rblBLtzFBVOeXeYRcluOsz4koE4JaAJaUtMtwdB04t89/1O/w1cDnyilFU='
@@ -12,7 +12,7 @@ const domain = "www.osstest17.ml"
 const sslport = 23023;
 const sslport = 23023;
 
 
 const bodyParser = require('body-parser');
 const bodyParser = require('body-parser');
-var app = express();
+var app = new Koa();
 app.use(bodyParser.json());
 app.use(bodyParser.json());
 let username; //username 저장
 let username; //username 저장
 app.post('/hook', function (req, res) {
 app.post('/hook', function (req, res) {