passport.use('local-register', new LocalStrategy(
    {usernameField: 'user_name', passwordField: 'password', passReqToCallback: true},

    function(req, name, password, done){ // done is a callback
        // asynchronous, waits for everything to be completed before executing
    console.log(req.body.email + " " + name + " " + password + " ");
        process.nextTick(function(){
            // search database for email that matches the registration email
            User.findOne({'local.email': req.body.email}, function(err, user){ // check database for email given in register
                if(err) // if there is an error return to callback err
                    return done(err);
                if(user){ // if there is an email match, return to register and display flash message
                    return done(null, false, req.flash('registerMessage', 'That email is already taken'));
                } else { // otherwise create a new user
                    var newUser = new User();
                    newUser.local.username = name;
                    newUser.local.password = password;
                    newUser.local.email = req.body.email;

                    newUser.save(function(err){
                        if(err)
                            throw err;
                    return done(null, newUser); // return done with no error and the newUser
                    });
                }
            })
        });
    }));