code: function(url, dest, cb) {
        var get = request(url);
        get.on('response',  function (res) {
          res.pipe(fs.createWriteStream(dest));
          res.on('end', function () {
            cb();
          });
          res.on('error', function (err) {
            cb(err);
          });
        });
      }
docs: Copy remote file to local hardrive
  @param  {string}   url  url of the remote file
  @param  {string}   dest destination where to copy file
  @param  {Function} cb   callback when file is copied
  @return {void}