diff --git a/docker-compose.yml b/docker-compose.yml
index 664e42e..d6165f0 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -20,6 +20,8 @@ services:
   redis:
     image: redis
     container_name: asciinema_redis
+    # see https://hub.docker.com/_/redis/ for more configuration options
+    # for this image
 
   sidekiq:
     image: asciinema/asciinema.org