init backend structure

+const express = require('express');
+const app = express();
+const bodyParser=require('body-parser');
+const morgan=require('morgan');
+const cors = require('cors');
+
+app.use( cors( ) );
+app.use(morgan('[:date[iso]] :method :status :url :response-time(ms) :user-agent'));    
+app.use(bodyParser.urlencoded({ extended: true }));
+app.use(bodyParser.json());
+app.use((req, res, next)=>{
+    res.header("Access-Control-Allow-Origin","*");
+    res.header("Access-Control-Allow-Headers","Origin, X-Requested-With, Content-Type, Accept");
+    next();
+  });
+app.use( '/api', require('./api') );
+
+app.listen(3000, ( ) => {
+    console.log('Server On!');
+});
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