diff --git a/config/cable.yml b/config/cable.yml
--- a/config/cable.yml
+++ b/config/cable.yml
@@ -6,4 +6,5 @@
 
 production:
   adapter: redis
-  url: redis://localhost:6379/1
+  url: <%= ENV.fetch("REDIS_URL") { "redis://localhost:6379/1" } %>
+  channel_prefix: cafe_grader_production