added mongose and express, modified server, for testing purpose added user controller, model and routes

server.js

@@ -1,7 +1,19 @@
 var express = require('express'),
   app = express(),
-  port = process.env.PORT || 3000;
+  port = process.env.PORT || 3000,
+  mongoose = require('mongoose'),
+  User = require('./api/models/userModel'), //created model loading here
+  bodyParser = require('body-parser');
+  
+// mongoose instance connection url connection
+mongoose.Promise = global.Promise;
+mongoose.connect('mongodb://localhost/Userdb'); 
 
+app.use(bodyParser.urlencoded({ extended: true }));
+app.use(bodyParser.json());
+
+var routes = require('./api/routes/userRoutes'); //importing route
+routes(app); //register the route
 app.listen(port);
 
 console.log('API server started on: ' + port);