socket.io and express sessions

I am programming a chat application using socket.io and express 4. Whenever a person login from login.html(client) . Server should remember his name and chat with person online.But in my case it just remember name which has logged in later (Suppose I login from John first and Ron later then it just remembers Ron.). Please Help I am totally new to node.js

var express = require('express')
, app = express()
, http = require('http')
, server = http.createServer(app)
, Twit = require('twit')
, io = require('socket.io').listen(server)
, os = require('os')
, open = require('open')
, bodyParser = require('body-parser')
, mysql = require("mysql");

server.listen(9383,'192.168.1.3');

app.use(bodyParser.urlencoded({ extended: false }));
var name;

app.get('/', function (req, res) {
  res.sendfile(__dirname + '/login.html');
});

app.post('/valid', function (req, res) {
  console.log("hello");
  console.log(req.body.pass);
  var username=req.body.email;
  var password=req.body.pass;

    var connection = mysql.createConnection({
      "hostname": "localhost",
      "user": "root",
      "password": "vk123",
      "database": "login"
    });

    connection.connect();

//Verifying whether person exist if exist it gets its name. 

    connection.query('SELECT * FROM id WHERE email=? AND password=?', [username,password], function(err, rows){

      if (err){
        throw err;
      }else{
        for (var i in rows) {
           console.log('name: ', rows[i].name);
           name=rows[i].name;
           res.redirect('http://192.168.1.3:9383/chat.html');

        }
      }

    });

     connection.end();
});

// It is obtaining message from client and sending back message and name.

io.sockets.on('connection', function(socket){
  socket.on('chat message', function(msg){
    var chatmsg=[];
    console.log(name);
    console.log(msg);
    chatmsg.push({chatname:name, msgtext:msg}); 
    console.log('message: ' +chatmsg[0].chatname);
    io.emit('chat message',chatmsg);
  });
});