Add nextcloud syncronisation

[hoellwerth]

Great app man, keep up the work! I have only one suggestion, which is adding Nextcloud syncronisation. It should help people like me who work on dispersed devices to keep up their plans.

[iman-salmani]

Thanks. In this link, I explained what going to do about syncing to other services. but before developing syncing section, the application needs code refactoring and adding necessary features.