Add docker-compose occ example

README.md

@@ -84,7 +84,10 @@ To use the [Nextcloud command-line interface](https://docs.nextcloud.com/server/
 ```console
 $ docker exec --user www-data CONTAINER_ID php occ
 ```
-
+or for docker-compose:
+```console
+$ docker-compose exec --user www-data app php occ
+```
 
 # Running this image with docker-compose
 The easiest way to get a fully featured and functional setup is using a `docker-compose` file. There are too many different possibilities to setup your system, so here are only some examples what you have to look for.