app.get('/:titless?', function(req, res) {
    PostDB.prototype.find({title: req.body.titless}, function(error, article_collection) {
console.log(article_collection);
console.log(error);
switch (req.params.format) {
      case 'json':
        res.send(documents.map(function(d) {
          return { title: d.title, id: d._id };
        }));
      break;
default:
        res.send('Format not available', 400);
      break;
}
  });
});