Update server

+const express = require('express');
+const fs = require('fs');
+const path = require('path');
+const HTTPS = require('https');
+
+const app = express();
+
+const domain = "2020105636.oss-2021.tk"
+const sslport = 23023;
+
+app.use(express.static(__dirname));
+
+app.get('/', function(req, res){
+    res.sendFile(__dirname + '/main.html');    
+});
+
+app.get('/main.html', function(req, res){
+    res.sendFile(__dirname + '/main.html');
+});
+
+app.get('/introduction.html', function(req, res){
+    res.sendFile(__dirname + '/introduction.html');
+});
+
+app.get('/calendar.html', function(req, res){
+    res.sendFile(__dirname + '/calendar.html');
+});
+
+
+app.get('/simulation.html', function(req, res){
+    res.sendFile(__dirname + '/simulation.html');
+});
+
+try {
+  const option = {
+    ca: fs.readFileSync('/etc/letsencrypt/live/' + domain +'/fullchain.pem'),
+    key: fs.readFileSync(path.resolve(process.cwd(), '/etc/letsencrypt/live/' + domain +'/privkey.pem'), 'utf8').toString(),
+    cert: fs.readFileSync(path.resolve(process.cwd(), '/etc/letsencrypt/live/' + domain +'/cert.pem'), 'utf8').toString(),
+  };
+
+  HTTPS.createServer(option, app).listen(sslport, () => {
+    console.log(`[HTTPS] Server is started on port ${sslport}`);
+  });
+} catch (error) {
+  console.log('[HTTPS] HTTPS 오류가 발생하였습니다. HTTPS 서버는 실행되지 않습니다.');
+  console.log(error);
+}
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