code: function(options){
      this.triggerMethod("initialize:before", options);
      this._initCallbacks.run(options, this);
      this.triggerMethod("initialize:after", options);
  
      this.triggerMethod("start", options);
    }
docs: kick off all of the application's processes. initializes all of the regions that have been added to the app, and runs all of the initializer functions