code: function(options) {
              var settings = $.extend({}, this.treegrid.defaults, options);
              return this.each(function() {
                  var $this = $(this);
                  $this.treegrid('setTreeContainer', $(this));
                  $this.treegrid('setSettings', settings);
                  settings.getRootNodes.apply(this, [$(this)]).treegrid('initNode', settings);
                  $this.treegrid('getRootNodes').treegrid('render');
              });
          }
docs: Initialize tree
  
  @param {Object} options
  @returns {Object[]}