add cached parameter for perf improvements

- https://docs.docker.com/docker-for-mac/osxfs-caching/
- https://blog.docker.com/2017/05/user-guided-caching-in-docker-for-mac/

docker-compose.yml

@@ -8,7 +8,7 @@ services:
     ports:
       - 20080:80                            # web server will use port 20080
     volumes:
-      - ./html:/var/www/html                # webroot `/var/www/html` will be synced with your local folder `./html`
+      - ./html:/var/www/html:cached         # webroot `/var/www/html` will be synced with your local folder `./html`
     depends_on:
       - db
       - mail
@@ -27,7 +27,7 @@ services:
     ports:
       - 23306:3306                          # database will use port 23306
     volumes:
-      - ./db:/var/lib/mysql                 # database in `/var/lib/mysql` will be synced with your local folder `./db`
+      - ./db:/var/lib/mysql:cached          # database in `/var/lib/mysql` will be synced with your local folder `./db`
     environment:
       MYSQL_DATABASE: redaxo
       MYSQL_USER: redaxo