Instalando a gem ‘pg’

Instalou o PostreSQL via brew e agora está precisando instalar a gem pg na sua maquina e não está conseguindo?

gem install pg -- --with-pg-config=/usr/local/Cellar/postgresql/9.x.x/bin/pg_config

resultado abaixo:

fabiotomio$ gem install pg -- --with-pg-config=/usr/local/Cellar/postgresql/9.3.4/bin/pg_config
Building native extensions with: '--with-pg-config=/usr/local/Cellar/postgresql/9.3.4/bin/pg_config'
This could take a while...
Successfully installed pg-0.17.1
invalid options: -f fivefish
(invalid options are ignored)
Parsing documentation for pg-0.17.1
Installing ri documentation for pg-0.17.1
Done installing documentation for pg after 2 seconds
1 gem installed

e seja feliz!