Definitions
  # <PATH> is the path to the Trac project /var/lib/trac/PROJECTNAME/

Create new Trac instance
  # trac-admin <PATH> initenv --inherit=/etc/trac/trac.ini

Change ownership to webserver
  # chown lighttpd:lighttpd <PATH> -R

Set permissions for webadmin
  # trac-admin <PATH> permission add authenticated TRAC_ADMIN
  # trac-admin <PATH> permission add authenticated TICKET_ADMIN