def sort_url(sort_on)
      url_params = @@params.clone
      if url_params.has_key? TableBuilder.params_sort_table
        if url_params[TableBuilder.params_sort_table].has_key? sort_on
          url_params[TableBuilder.params_sort_table][sort_on] = inverse_sorting(sort_on)
          return url_for(url_params)
        end
        url_params[TableBuilder.params_sort_table].delete sort_on
      end
      url_params[TableBuilder.params_sort_table] = { sort_on => :asc }
      url_for(url_params)
    end
def sort_url(sort_on)
      url_params = @@params.clone
      if url_params.has_key? TableBuilder.params_sort_table
        if url_params[TableBuilder.params_sort_table].has_key? sort_on
          url_params[TableBuilder.params_sort_table][sort_on] = inverse_sorting(sort_on)
          return url_for(url_params)
        end
        url_params[TableBuilder.params_sort_table].delete sort_on
      end
      url_params[TableBuilder.params_sort_table] = { sort_on => :asc }
      url_for(url_params)
    end
Return an url for sorting
 Add the param sorting_table[name]=direction to the url
 Add the default direction: :asc