What and where is the method register! in restful authentication?

A newbie question - I am learning restful authentication but I cant
find what or where the method register! is when used in the following
code:

@user.register! if @user && @user.valid?

Thanks.

User acts as a state machine. Transitions automatically get methods
that are named after them with a “!” at the end. Look for a
transition called register and it shows from what state to what state
this “register” can occur.

Ramon T.

On Sat, Jan 31, 2009 at 5:15 PM, thomasalbert

Thanks Ramon,

Never heard of finite state machines or acts_as_state_machine before,
I have been chasing it on the web - more to learn.