module.exports = function (req, res, next) {
  res.header ('Access-Control-Allow-Origin', '*');
  res.header ('Access-Control-Allow-Headers', 'Origin, Content-Type');
  res.header ('Access-Control-Allow-Methods', 'GET, POST, PUT');
  res.header ('Access-Control-Allow-Credentials', 'true');
  next ();
};