Update cable adapter to use Redis

Change cable adapter from async to redis and add URL configuration.

Author: damianlegawiec

config/cable.yml

@@ -1,5 +1,6 @@
 development:
-  adapter: async
+  adapter: redis
+  url: <%= ENV.fetch("REDIS_URL", "redis://localhost:6379/1") %>
 
 test:
   adapter: test