starting the server at boot

Hello;

If I add the line:
-------------------
 su -c 'pg_ctl start -D /usr/local/pgsql/data/ -l
/usr/local/pgsql/data/logfile' postgres
-------------------
to /etc/rc.d/rd.local.
Is there a way this could work when I don't boot as root, but as a common
user?

(I should be able to automatically pass a password, and I don't know how)

Thanks and regards

Javier Garcia