Using RBoard with an existing database with existing user model


I have an existing application running with a user model and

Now, I have copied the rboard (rails 3) repository from github and
would like to run this forum on a subdomain, and letting it point to
the same database that I'm using for my application (so people can use
same login for forum & site)

I have another auth system (authlogic) than rboard's using. Attributes
for my user model are different from rboard's. Can anybody help me out
a bit more on how to integrate rboard with my existing database.

Shall I just edit my existing user model to the attributes/methods
that rboard's using?