passport.use('local-signup', new LocalStrategy({
  usernameField: 'username',
  passwordField: 'password',
  passReqToCallback: true
}, function(req, username, password, cb) {
  process.nextTick(function() {
    User.findOne({
      username: username
    }, function(err, data) {
      if (err)
        return cb(err)
      if (data)
        return cb(null, false, req.flash('signupMessage', 'That username is already taken.'));


      // Insert method goes here.
    var newUser = new User()

    newUser.username = username
    newUser.password = password

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

<input type="text" name="username" placeholder="username"/>
<input type="text" name="fullname" placeholder="fullname" />
<input type="text" name="emaill" placeholder="email"/>
<input type="text" name="password" placeholder="password"/>