app.post('/auth', function(req,res) {
  //console.log(req.body.username + ' ... ' + req.body.password);
  console.log(crypto.createHash('md5').update('133715').digest("hex"));

  var user_collection = function (err, collection) {
    collection.find({user: req.body.username,pass: crypto.createHash('md5').update(req.body.password).digest("hex")}).toArray(function(err, user_results) {
      console.log(user_results);
      res.redirect('/');
    });
  };

  db.open(function(err, p_client) {
    db.collection('user', user_collection);
  });

});