updating model with nested collection attribute

gistfile1.txt

Project = Backbone.Model.extend({
  
  initialize: function() {
    _.bindAll(this, 'getRules', 'saveRules');
    this.getRules();
    this.rules.bind('add', this.saveRules);
    this.rules.bind('remove', this.saveRules);
  },

  getRules: function() {
    var rules = this.get("rules");
    this.rules = new RulesCollection(rules);
  },
  
  saveRules: function() {
    this.set({ "rules": this.rules });
  },
  
  save: function() {
    this.collection.update(this);
  }

});