Class Ext.grid.RowNumberer

This is a utility class that can be passed into a Ext.grid.ColumnModel as a column config that provides an automatic row numbering column.
Usage:

// This is a typical column config with the first column providing row numbers
 var colModel = new Ext.grid.ColumnModel([
    new Ext.grid.RowNumberer(),
    {header: "Name", width: 80, sortable: true},
    {header: "Code", width: 50, sortable: true},
    {header: "Description", width: 200, sortable: true}
 ]);