server.js

// POST /todos
app.post('/todos', middleware.requireAuthentication, function(req, res) {
	var body = _.pick(req.body, 'description', 'completed');

	db.sequelize.transaction(function(t) {
		var t;

		return db.todo.create(body).then(function(todo) {
			t = todo;
			return req.user.addTodo(todo)
		}).then(function() {
			return t.reload();
		})
	}).then(function(todo) {
		res.json(todo.toJSON());
	}, function(error) {
		// Handle specific errors here
	});
});