Ubuntu + RoR + Firebird OR Ubuntu + RoR + PostgreSQL ?

Dear friends,
I am starting to build a system for an university using RoR. I would
like to use Firebird because I worked with it for a long time and I
love it! In this new project I will use a lot of stored procedures,
data referential integrity and so on. But when I looked for the
Firebird adapter for Ruby and the activerecord for Firebird adapter,
it seems to have so few support and so few users, that I am afraid
about its future.
This is one of the most important e-mails I've sent on my life....! If
I have to start using Postgre the time is now. But with a great pain
on my heart for the Firebird.
Could someone give me a good advice?
Thank you very much!