i will use **nodemon start** command but getting error. Can you help me?

> 
> ReferenceError: server is not defined
> 
> 
> 

app.js
------

```
var fs = require('fs');
var express = require('express');
var path = require('path');
var other = require('./others');

var app = express();

app.get('/index', other.index);
app.get('/', other.index);

server.listen(8006);

```

others.js
---------

```
var path = require('path');

module.exports.index = function(req, res)
{
    res.sendFile(path.join(__dirname, 'index.html'));
}

```