Short url generator specifying hash

gistfile1.js

'use strict';

var short = require('short');

short.connect('mongodb://localhost/short');

short.generate({
  hash: 'google',
  URL: 'http://www.google.com/'
}).then(function(shortUrlDoc) {
  // this should be `google`, but it's still randomly generated
  console.log(shortUrlDoc.hash);
}, function (err) {
  console.log(err);
});