Which is the easiest Forum to integrate with tank_auth

[eluser]codeignite_noob[/eluser]
I am quite new to Codeigniter. On reading up on all the authentication libraries I decided to go with tank_auth. I now have an application running quite smoothly and want to expand it to include a forum-like functionality.
Which forum is the easiest to integrate with tank_auth authentication. If none, are there any libraries that I can use instead? I want to avoid creating a forum from scratch if I can.
Thanks much.