added multi sort link
example usage in view:

<%=multi_sort_link(@q, :state_name, ["state_country asc", :state_name]) %>
#@q = filter params
#:state_name - field label
#[] - array of fields, can be symbol, can be text
# if you have only 1 column, you may add only 1 field [:state_name]

if sort order is specified, it will be fixed,
other wise, it will allow toggle between asc and desc depending on current sort

please feel free to improvised :)