1\. Create a new subdirectory for rainloop and download the RainLoop installer: ``` mkdir data/web/rainloop curl -o data/web/rainloop/installer.php -s http://repository.rainloop.net/installer.php ``` 2\. Run the installert from within the PHP-FPM mailcow container and delete the installer: ``` docker exec -it $(docker ps -qf name=php-fpm-mailcow) php /web/rainloop/installer.php rm data/web/rainloop/installer.php ``` 3\. Login to `${MAILCOW_HOSTNAME}/rainloop/?admin` to set a password. The default credentials are `admin`:`12345`. Add and configure a new domain as you need. Use "dovecot" as IMAP server name and "postfix" as SMTP server name.  