App installation in docker container

Hello,

everytime I’m installing an app in nextcloud it is working till the next container start.

I can see in the apps directory that the app is available after installation (f.e. calendar).
After stopping the container the app files are still in the local filesystem.
But with the next start of the container they will be deleted.

What can I do?

My docker-compose.yaml for nextcloud looks like:
nextcloud:
image: nextcloud
volumes:
- type: bind
source : /var/lib/docker_data/nextcloud/data
target : /var/www/html/data
- type: bind
source : /var/lib/docker_data/nextcloud/config
target : /var/www/html/config
- type: bind
source : /var/lib/docker_data/nextcloud/apps
target : /var/www/html/apps
networks:
- nextcloud
restart: always
container_name : nextcloud-nextcloud
depends_on:
- mariadb
hostname: “nextcloud”
environment:
- VIRTUAL_HOST=nextcloud.local
- VIRTUAL_PORT=8080