Minor fixes. (#4639)

config/cable.yml

@@ -6,5 +6,5 @@ test:
 
 production:
   adapter: redis
-  url: <%= ENV.fetch("REDIS_URL")
+  url: <%= ENV.fetch("REDIS_URL", "") %>
   channel_prefix: greenlight_production

docker-compose.yml

@@ -8,7 +8,6 @@ services:
     volumes:
       - ./data/postgres/14/database_data:/var/lib/postgresql/data
     environment:
-      - POSTGRES_DB=postgres
       - POSTGRES_USER=postgres
       - POSTGRES_PASSWORD=