MYSQL_SERVER <SQL_HOST>
MYSQL_USERNAME <SQL_UNPRIVILEGED_USER>
MYSQL_PASSWORD <SQL_UNPRIVILEGED_PASSWORD>
MYSQL_PORT 3306
MYSQL_DATABASE <SQL_DB>
MYSQL_USER_TABLE mail_users
MYSQL_CRYPT_PWFIELD password_enc
MYSQL_UID_FIELD uid
MYSQL_GID_FIELD gid
MYSQL_LOGIN_FIELD username
MYSQL_HOME_FIELD homedir
MYSQL_MAILDIR_FIELD maildir
