Add example command for copying (#2327)

As for #2266 and the re-appearing message IMHO, it is quite convenient to have a command to copy here if you just have not changed any config files…

Signed-off-by: rugk <[email protected]>

README.md

@@ -242,6 +242,10 @@ During a fresh Nextcloud installation, the latest version (from the image) of th
 The copied files, however, are **not** automatically overwritten whenever you update your environment with a newer Nextcloud image. This is to prevent local changes in `/var/www/html/config` from being unexpectedly overwritten. This may lead to your image-specific configuration files becoming outdated and image functionality not matching that which is documented.
 
 A warning will be generated in the container log output when outdated image-specific configuration files are detected at startup in a running container. When you see this warning, you should manually compare (or copy) the files from `/usr/src/nextcloud/config` to `/var/www/html/config`.
+A command to copy these configs would e.g. be:
+```console
+docker exec <container-name> sh -c "cp /usr/src/nextcloud/config/*.php /var/www/html/config"
+```
 
 As long as you have not modified any of the provided config files in `/var/www/html/config` (other than `config.php`) or only added new ones with names that do not conflict with the image specific ones, copying the new ones into place should be safe (but check the source path `/usr/src/nextcloud/config` for any newly named config files to avoid new overlaps just in case).