DB runs as user + add notes.md for nextcloud-db volume relocation

notes.md

@@ -0,0 +1,16 @@
+# Nextcloud-db has moved
+
+Since commit e4ede925a8ce09b177206f30487a889da9e10334, nextcloud-db directory (mapped on /var/lib/mysql) has moved from
+``/data/nextcloud-db`` to ``$HOST_CONFIG_PATH/nextcloud-db`` (*/data/config/nextcloud-db by default*).
+
+To ensure a smooth transition, you will have to move the directory nextcloud-db into the correct new location, then run some commands to fix the schema:
+
+```sh
+mv /data/nextcloud-db/ /data/config/
+./update-all.sh
+source .env
+docker exec -it nextcloud-db mysql_upgrade -u root -p${MYSQL_ROOT_PASSWORD}
+docker restart nextcloud nextcloud-db
+```
+
+Ensure everything runs nicely by looking at nextcloud-db and nextcloud logs, and by accessing your Nextcloud web UI.

services/nextcloud.yaml

@@ -3,6 +3,7 @@ services:
       image: mariadb:10
       container_name: nextcloud-db
       command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW --innodb-file-per-table=1 --skip-innodb-read-only-compressed
+      user: ${PUID}:${PGID}
       restart: always
       environment:
         - MYSQL_ROOT_PASSWORD=${MYSQL_ROOT_PASSWORD}