Update README

README.md

@@ -32,6 +32,8 @@ Using this playbook, you can get the following services configured on your serve
 
 - (optional, advanced) the [matrix-synapse-ldap3](https://github.com/matrix-org/matrix-synapse-ldap3) LDAP Auth password provider module
 
+- (optional, advanced) the [synapse-simple-antispam](https://github.com/t2bot/synapse-simple-antispam) spam checker module
+
 - (optional, advanced) the [Matrix Corporal](https://github.com/devture/matrix-corporal) reconciliator and gateway for a managed Matrix server
 
 - (optional) the [mautrix-telegram](https://github.com/tulir/mautrix-telegram) bridge for bridging your Matrix server to [Telegram](https://telegram.org/)