Node. Js/Mongodb: How Can I Use Module. Exports to Pass a Localhost Database Url to Server. Js File?

I have a problem with connection to a database with mongoose on localhost.

In my server.js file I have:

var express     = require('express');
var app         = express();                        //Create our app with express
var mongoose    = require('mongoose');              //Mongoose for mongoDB
var database    = require('./config/database.js');  //Load the database config

...

//Configuration =====================
mongoose.connect('database.url');   //Connect to mongoDB database

...

In my database.js file I have:

// Config/database.js

module.exports = {
url : 'mongodb://127.0.0.1:27017/test'
};

The error I get in my node.js command prompt is:

events.js:141
  throw er; // Unhandled 'error' event
  ^

Error: failed to connect to [database.url:27017]
at null.<anonymous> (C:\*filepath*\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\server.js:540:25)
at emitThree (events.js:97:13)
at emit (events.js:175:7)
at null.<anonymous> (C:\*filepath*\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\connection_pool.js:140:15)
at emitTwo (events.js:87:13)
at emit (events.js:172:7)
at Socket.<anonymous> (C:\*filepath*\node_modules\mongoose\node_modules\mongodb\lib\mongodb\connection\connection.js:478:10)
at emitOne (events.js:77:13)
at Socket.emit (events.js:169:7)
at emitErrorNT (net.js:1256:8)

When I use mongodb://127.0.0.1:27017/test in place of database.url it works just fine.

I'm currently using node.js v4.2.6 and mongodb 3.2 on Windows 10.

How can I get module.exports to pass the url to the server.js?