sequelize-belongsTo.js

var Sequelize = require('sequelize');
var sequelize = new Sequelize('db','db_user','db_password');
var chainer = new Sequelize.Utils.QueryChainer

var User = sequelize.define('User', {name: Sequelize.STRING}, {timestamps: false})
var City = sequelize.define('City', {name: Sequelize.STRING}, {timestamps: false})

var joe = User.build({name: 'Joe'});
var london = City.build({name: 'London'});

User.belongsTo(City);

sequelize.sync().success(function(){
    chainer
        /* will not work ! see https://github.com/sequelize/sequelize/issues/1954#issuecomment-46954587
        .add(joe.save())
        .add(london.save())
        .add(joe.setCity(london))
        */
        .add(joe, 'save')
        .add(london, 'save')
        .add(joe, 'setCity', london)
        .runSerially()
        .success(function(){ console.log('all good');})
        .error(function(err){ console.log(err);});
});