Update mongo.js

mongo.js

 const mongoose = require('mongoose')
 
 // Replace with the URL of your own database. Do not store the password on GitHub!
-const url = 'mongodb+srv://fullstack:Koodaanko247@clusterphonebook-duq8b.mongodb.net/fullstack-contacts'
+const url = 'mongodb+srv://fullstack:xxx@clusterphonebook-duq8b.mongodb.net/fullstack-contacts'
 
 mongoose.connect(url, { useNewUrlParser: true })