i don't see how auto_link has anything to do with his question. he
asked about adding a class attribute using link_to
and to answer your question, no. autolink just replaces urls and/or
email addresses in a string with the appropriate anchor tag. doesn't
matter where the url goes.
there's a difference. one replaces urls and email addresses with
anchor tags in a string, the other generates an anchor tag from a name
and url (and any options).