Add cache volume for Rails caches

docker-compose.yml

@@ -12,6 +12,7 @@ services:
       - redis
     volumes:
       - ./:/app
+      - cache:/app/tmp/cache
     ports:
       - 3000:3000
 
@@ -26,4 +27,7 @@ services:
       - 5432:5432
     environment:
       POSTGRES_PASSWORD: justask
-      POSTGRES_DB: justask_development
+      POSTGRES_DB: justask_development
+
+volumes:
+  cache: