upgrade postgres from 8 to 9

> pg_ctl -D /usr/local/var/postgres start
> pg_dumpall > backup.sql
> pg_ctl -D /usr/local/var/postgres stop
> mv /usr/local/var/postgres /usr/local/var/postgres.bak

> brew install postgresql
> initdb /usr/local/var/postgres
> pg_ctl -D /usr/local/var/postgres start
> psql -f backup.sql postgres
> rm -r /usr/local/var/postgres.bak