# File app/models/change.rb, line 92
   def undo(author)
    @changes = Change.find(:all, :conditions => ["object_path = ? and date < ? and data_changed = ?", self.object_path, self.date, self.data_changed])
    if @changes[@changes.length-2]
    @changes[@changes.length-2].revert(author)  #Change the field back to how it was last change.
    @changes_to_delete = Change.find(:all, :conditions => ["object_path = ? and date >= ? and data_changed = ?", self.object_path, self.date, self.data_changed]) 
    @changes_to_delete.each { |c| c.destroy }  #Delete all changes after and including this one
    end
   end