Add Nextcloud

Add Nextcloud, fork of Owncloud

README.md

@@ -477,6 +477,7 @@ Some [Groupware](#groupware) solutions also feature file sharing and synchroniza
 
   * [Git Annex](http://git-annex.branchable.com/assistant/quickstart/) - File synchronization between computers, servers, external drives
   * [Kinto](https://kinto.readthedocs.org) - Kinto is a minimalist JSON storage service with synchronisation and sharing abilities. ([Source Code](https://github.com/Kinto)) `Apache 2.0` `Python`
+  * [Nextcloud](https://nextcloud.com/) - Access & share your files, calendars, contacts, mail & more from any device, on your terms ([Source Code](https://github.com/nextcloud/server)) `AGPLv3` `MIT`
   * [OpenSSH/SFTP](http://www.openssh.com/) - Secure File Transfer Program. ([Source Code](http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh)) `BSD` `C`
   * [Samba](https://www.samba.org/) - Samba is the standard Windows interoperability suite of programs for Linux and Unix. It provides secure, stable and fast file and print services for all clients using the SMB/CIFS protocol. ([Source Code](https://git.samba.org/samba.git/)) `GPLv3` `C`
   * [Seafile](https://www.seafile.com/en/home/) - File hosting and sharing solution primary for teams and organizations. ([Demo](https://seacloud.cc/demo)) `GPLv2`