auto-pull.js

var exec = require('child_process').exec;

// alternative ultra-short ECMA2015 version
// setInterval(a=>require('child_process').exec('git pull',(b,c,d)=>{console.log(b||c||d)}),6e4)

setInterval(function() {
  exec('git pull', puts);
}, 60 * 1000);

function puts(error, stdout, stderr) {
  console.log(error || stderr || stdout);
}

Usage

Place auto-pull.js into whatever directory git pull is normally run from. Vanilla ES5 with no external dependencies other than child_process from the node standard library, so it should run in most node environments. Change the value of the argument to the setInterval function in order to have the pulls more or less frequent, currently set to 60 seconds.