I have configured postfix + dovecot as per this guide, originally published at http://neranjara.org/article/title/How_to_configure_PostFix_and_Dovecot_for_Virtual_Users_with_out_a_Database_ now defunct. I used virtual users option. Everything works great.
Now I'd like to configure a specific email address to forward all emails to another address but to retain a copy of email in the original mailbox.
How do I achieve this?