FreefileSync

A nice file syncronising tool is found here: link

They also offer a repository but that seems not to work for Ubuntu 16.04.

Just download the file. Unzip it and start the file "freefilesync" . The program should start and for easy use, you could pin the starter in the unity bar.

When starting freefile sync you can select two folders. They will be compared and you can choose how to update the contants of these folders in a way that they are synchronised. It works fast and convenient.