gistfile1.txt

App.CreateUserRoute = Em.Route.extend({
  
	transaction: null,

	model: function() {
		this.transaction = App.store.transaction();
		return this.transaction.createRecord(App.User);
	},


	events: {

		submit: function(user) {
			
			var errors = {};
			if (Em.isEmpty(user.get('name')))
				errors.name = "Name is required";

			if (!$.isEmptyObject(errors)) {
				user.set('errors', errors);
				user.set('isValid', false);
				return;
			}

			var self = this;
			user.one('didCreate', function() {
				this.transitionTo('user', user);
			});
			this.transaction.commit();
		}
	},

	exit: function() {
		this.transaction.rollback();
	}
});

For anyone coming from StackOverflow / other sources... Transactions are no more.

See: https://github.com/emberjs/data/blob/master/TRANSITION.md#transaction-is-gone-save-individual-records