Implementing "coins" to my users on passportjs and changing them

I actually have 2 questions. One is what is the best way to go about adding other information to my user object? I have a very simple passportjs login/register system and I want to expand and also add things like coins and other things that are specific to a user's account. Currently, I just added a new property called "coins" along with the password/email and stuff.

My second question is with my coins property for my user object, how do I edit it? Currently I just have a simple request to add a coin for the user and it isn't working.

router.get('/coin', function(req, res) {
    User.getUserByUsername(req.user.username, function(err, user){
        user.coins = user.coins + 1
        console.log(user.coins)
   });
    res.redirect('/')
});

It is just console logging 1 every time I press the button(the button calls for /coin)

via anduyang