Enable passport

app.js

var passport = require('passport');
var TwitterStrategy = require('passport-twitter').Strategy;
var findOrCreateProfile = require('./findOrCreateProfile');

…

app.use(passport.initialize());
app.use(passport.session());
var Account = require('./models/account');

…

passport.use(new TwitterStrategy({
    consumerKey: '...',
    consumerSecret: '...',
    callbackURL: ”http://localhost:3000/auth/twitter/callback"
  },
  function(token, tokenSecret, profile, done) {
    findOrCreateProfile({twitterId: profile.id}, profile, done);
  }
));
passport.serializeUser(Account.serializeUser());
passport.deserializeUser(Account.deserializeUser());