Automatic deployement -- Nodejs, Pm2 and github

hook.js

var http = require("http");  
var exec = require("child_process").exec;  
var createHandler = require("github-webhook-handler");  
var handler = createHandler({ path: "/", secret: "လျှို့ဝှက်ချက်"});

http.createServer(function(req, res) {  
  handler(req, res, function (err) {
    res.statusCode = 404;
    res.end("no such location");
  });
}).listen(9999);

handler.on("push", function (event) {  
  var repo = event.payload.repository.name;
  var comps = event.payload.ref.split("/");
  if(comps[2] !== "master") {
    console.log("Received a push on %s and no build has is triggered", comps[2]);
    return;
  }
  console.log("Received a push on master, build started...");
  exec("cd ~/" + repo + " && git pull origin master && npm install && pm2 restart " + repo, function(error, stdout, stderr) {
    if(error != null) {
      console.log("Error during the execution of redeploy: " + stderr);
    }
  });
});