restful_authentication does it self. you just have to add the attribute column that restful suggest. Just create user table with the columns suggested by restful_auth. You find your ans in "last_login_at" attribute

restful_authentication actually supports a range of different auth types (cookie/persistence/basic auth) so it depends on which scenario youre using. That said tho - even when using a database it doesn't record the actual login time, etc. (it just compares the incoming credentials). Would be very easy to add a hook of your own in your generated model that recorded a user's last logged in time in the authenticate method.