add custom cron file to nextcloud image #79

Job	Run time
Build App Containers (indico) / Build indico	2m 32s
Build App Containers (etherpad) / Build etherpad	47s
Build App Containers (minecraft) / Build minecraft	27s
Build App Containers (limesurvey) / Build limesurvey	35s
Build App Containers (nextcloud) / Build nextcloud	1m 38s
Build App Containers (sogo) / Build sogo	2m 43s
	8m 42s

Provide feedback