using pg on snow leopard

I have a macbook running snow leopard. I recently installed postgresql
9.0 on it. I also installed pg with the following command:

sudo env ARCHFLAGS='-arch x86_64' gem install pg

The result was fine:

Building native extensions. This could take a while...
Successfully installed pg-0.9.0
1 gem installed
Installing ri documentation for pg-0.9.0...
Installing RDoc documentation for pg-0.9.0...

I launched rails and when I tried to access http://localhost:3000/ I
got the following error:

LoadError (no such file to load -- pg):

do you added in config/environment.rb?

config.gem ‘pg’

See Erol Fornoles answer today to my same question yesterday...

See Erol Fornoles answer today to my same question yesterday...

Ah, our messages must have "crossed in the mail". My apologies for the
duplicate message. For those searching for it, Scott's message is
entitled:

LoadError (no such file to load -- pg), OS X, Rails 3, Ruby 1.9.2,
Postgres Options