It seems Zotero still doesn't support 3rd party cloud service (Dropbox, Google Drive, iCloud etc).
I really recommend Paperpile, especially its Chrome extension. In my opionion, nothing beats Google Docs on collaborative writing.
I really recommend Paperpile, especially its Chrome extension. In my opionion, nothing beats Google Docs on collaborative writing.
https://www.zotero.org/support/kb/webdav_services
You also have an option to use the Zotfile extension to sync with other services.