increase availability of node application

cluster_availability.js

// to increase the availability of the application
// we create new worker using fork() method if the worker is crushed.
// so that we can increase our applications availability.
if (code !== 0 && !worker.exitedAfterDisconnect) {
    console.log(`Worker ${worker.id} crashed. \nStarting a new worker...`);
    cluster.fork();
}