Get more from RM 5.4 in Padrino project?

Hello. The work I'm doing now does not require a full Rails approach, so I'm using Padrino, with ActiveRecord as the ORM and Ruby 2 with RVM and a gemset.

What can I do to make RM more helpful in this context, if anything?  For example, RM doesn't know about .find_by_id, and I haven't even tried to use generators and the like.

I am, btw, rather new to Ruby but not to software development in general.

Thanks for any suggestions.