diff --git a/README.md b/README.md
index 3b5cd00..c75a1a4 100755
--- a/README.md
+++ b/README.md
@@ -6,3 +6,9 @@ Variables:
 * `DUCKDNS_TOKEN`: Duck DNS Account Token
 * `DUCKDNS_DOMAIN`: Full Duck DNS domain (e.g. `test.duckdns.org`)
 * `LETSENCRYPT_EMAIL`: Email used for certificate renewal notifications
+
+Volumes:
+* `<certs>:/etc/letsencrypt`: A named or hosted volume which allows SSL certificates to persist and be accessed by other containers
+
+TODO:
+* Implement tests so `depends_on` can be used in docker-compose to prevent other containers from initialising until certificates are ready