TypeError: passport.authenticate is not a function at
module.exports (D:xampphtdocsLive-Q-A-Approutersindex.js:12:30)

app.post('/login', passport.authenticate('local-login', {
    successRedirect : '/',
    failureRedirect : '/login',
    failureFlash : true
}));

require('./config/passport')(passport);
app.use(morgan('dev')); // log every request to the console
app.use(cookieParser()); // read cookies (needed for auth)
app.use(bodyParser.json()); // get information from html forms
app.use(bodyParser.urlencoded({extended: true}));
app.set('view engine', 'jade');

app.use(express.static('build'));

// required for passport
app.use(session({ secret: 'webtech2liveQandA', saveUninitialized: false,  resave: false, maxAge: new Date(Date.now() + 3600000), expires: new   Date(Date.now() + 3600000)})); // session secret
app.use(passport.initialize());
app.use(passport.session());
app.use(flash()); // Flash messages from session

require('./routers/index')(app, passport); // load our routes
require('./routers/discussion.js')(app, passport);
require('./models/question.js')(app, passport);
// include our router
app.use('/', require('./routers'));
app.use('/discussion', require('./routers/discussion'));

var passport = require('passport');
var LocalStrategy   = require('passport-local').Strategy;
var User = require('../models/user');

module.exports = function(passport) {
passport.serializeUser(function(user, done) {
    done(null, user.id);
});

passport.deserializeUser(function(id, done) {
    User.findById(id, function(err, user) {
        done(err, user);
    });
});

// SIGNUP
passport.use('local-signup', new LocalStrategy({
    usernameField : 'username',
    passwordField : 'password',
    passReqToCallback : true
},
function(req, username, password, done) {
    User.findOne({ 'local.username' :  username }, function(err, user) {
        if (err){
            return done(err);
        }
        if (user) {
            return done(null, false, req.flash('signupMessage', 'That username is already taken.'));
        } else {
            var newUser = new User();

            newUser.local.username = username;
            newUser.local.password = newUser.generateHash(password);

            newUser.save(function(err) {
                if (err){
                    throw err;
                }
                return done(null, newUser);
            });
        }
    });
}));

passport.use('local-login', new LocalStrategy({
    usernameField : 'username',
    passwordField : 'password',
    passReqToCallback : true
},
function(req, username, password, done) {
    User.findOne({ 'local.username' :  username }, function(err, user) {

        if (err)
            return done(err);

        if (!user)
            return done(null, false, req.flash('loginMessage', 'No user found.'));

        if (!user.validPassword(password))
            return done(null, false, req.flash('loginMessage', 'Oops! Wrong password.'));

        return done(null, user);
    });
}));
};