Fix preview command

nextcloud/image/Dockerfile

@@ -9,6 +9,6 @@ COPY supervisord.conf /
 
 ENV NEXTCLOUD_UPDATE=1
 
-RUN echo '*/15 * * * * php /var/www/html/occ preview:generate' >> /var/spool/cron/crontabs/www-data
+RUN echo '*/15 * * * * php /var/www/html/occ preview:generate-all' >> /var/spool/cron/crontabs/www-data
 
 CMD ["/usr/bin/supervisord", "-c", "/supervisord.conf"]]