* 'update_config_0.3.x-0.4.py'
    - fixed code for view dovecot_user
* 'create_tables.pgsql'
    - updated view dovecot_user (extra field »mail«)
* 'UPGRADE'
    - fixed filename (update_0.3.x-0.4.sh -> upgrade.sh)
    - added hints for view perms and user_query
* 'INSTALL'
    - replaced mail_extra_groups with mail_privileged_group
    - updated user_query
If you have installed vmm 0.3.x you have to proceed this steps:
    * stop Postfix and Dovecot
    * backup/dump your database.
    * backup/dump your database!
    * execute upgrade.sh
    * set permissions for replaced views:
        GRANT SELECT ON dovecot_user TO your_dovecot_dbuser;
        GRANT SELECT ON postfix_transport TO your_postfix_dbuser;
    * update user_query in /etc/dovecot/dovecot-sql.conf:
        user_query = \
            SELECT home, uid, gid, mail FROM dovecot_user WHERE userid='%u'
    * edit the pgsql parameters hosts, user, password and dbname in:
        $(postconf -h config_directory)/pgsql-smtpd_sender_login_maps.cf
        $(postconf -h config_directory)/pgsql-transport.cf
        $(postconf -h config_directory)/pgsql-virtual_mailbox_domains.cf
    * check the value of option transport in section misc in
      /usr/local/etc/vmm.cfg
    * start Dovecot and Postfix
else:
    * read INSTALL