$ brew uninstall postgresql
$ gem uninstall pg # ALL OF THEM
$ rm -fr /usr/local/var/postgres
$ launchctl unload -w ~/Library/LaunchAgents/homebrew.mxcl.postgresql.plist
$ pg_ctl -D /usr/local/var/postgres stop -s -m fast # WE SHOULD HAVE ALL postgres SERVERS & PROCESSES STOPPED BY NOW
$ brew install postgres
$ env ARCHFLAGS="-arch x86_64" gem install pg
$ echo "DONE." >> /dev/null