config.yml.erb in roo_on_rails-2.0.0.pre.pre.2

- old
+ new

@@ -30,10 +30,10 @@
     docker:
       - image: ruby:<%= ruby %>-alpine
       - image: postgres:9.6-alpine
         environment:
           PGDATA: /dev/shm/pgdata
-      - image: redis:3-alpine
+      - image: redis:4-alpine
     steps:
       - checkout
 
       - run:
           name: Setup RAM disk