iOS 8 added storage providers which allows 3rd party apps to provide a place for apps to sync and store files. This would allow you to easily sync with tons of services (Like Google Drive, owncloud, OneDrive, etc) without having to add them individually like you've done with Dropbox. There's a part of this API called "open" which means that changes are immediantly sent back after you modify it which easily achieves what you need.
iOS 8 added storage providers which allows 3rd party apps to provide a place for apps to sync and store files. This would allow you to easily sync with tons of services (Like Google Drive, owncloud, OneDrive, etc) without having to add them individually like you've done with Dropbox. There's a part of this API called "open" which means that changes are immediantly sent back after you modify it which easily achieves what you need.