title: Adding extra information in user object in passport.js or somewhere in session
body: <p>I want to add custom keys in the user object that is coming from mongodb and that is going to be used by passport.js but i wonder why i can't add more keys to that object, here is my code.</p>
  
  <pre><code>passport.use(new LocalStrategy(
      function(username, password, done) {
          Users.model(false).findOne( {email:username,password:encodePassword(password) }, function(err, user) {
              if( err ){ // validation failed
                  console.log('Error Occurred');
                  return done(err);
              }
              else if(user != null){
  
                  user['customKey'] = "customValue"; // it is not setting
  
                  console.log(user);
  
                  return done(null, user);
              }
              else {
  
                  return done(null, false, { message: 'Incorrect username.' });
              }
          });
      }
  ));
  ///Session handling
  passport.serializeUser(function(user, done) {
      done(null, user.id);
  });
  
  passport.deserializeUser(function(id, done) {
      Users.model(false).findById(id, function(err, user) {
          done(err, user);
      });
  });
  </code></pre>