fixing heroku

package.json

@@ -2,7 +2,7 @@
   "name": "workspace",
   "version": "1.0.0",
   "description": "",
-  "main": "index.js",
+  "main": "server.js",
   "scripts": {
     "test": "echo \"Error: no test specified\" && exit 1"
   },

server.js

@@ -1,10 +1,12 @@
 var express = require('express');
 var app = express();
 
+var port = process.env.PORT || 3000;
+
 app.get('/', function(req, res){
     res.send('works');
 })
 
-app.listen(3000, function(){
+app.listen(port, function(){
     console.log('listening on port ' + process.env.PORT);
 })