Enabling HTTPS for NextCloud on CasaOS

1. Please add the following env var into NextCloud's Docker Compose: NEXTCLOUD_OVERWRITEPROTOCOL=https
2. Afterwards, go to NextCloud's directory (which you can find using the app's settings, and check the volume mount point) and edit the config/config.php file.
3. Insert overwriteprotocol' => 'https', anywhere you'd like.
4. Also, add your domain name to trusted_domains attribute, and change the overwrite.cli.url to the same domain name.

Afterwards, re-start the app. Now, you can reach to your NextCloud instance using the new domain.