Added an example of how to concat() user and domain.
Added an example of how to concat() user and domain.

Distrotech/dovecot,damoxc/dovecot,Distrotech/dovecot,Distrotech/dovecot,Distrotech/dovecot,damoxc/dovecot,damoxc/dovecot,damoxc/dovecot,damoxc/dovecot,Distrotech/dovecot