How to sync my local database of my web app to database of my deployed web app?

So my project is a school distributed system based on django web framework. My web app will be deployed in every school on their local computers. And all of the data on those computer will by synced with a main server on my side. What I want is how to implement a solution that would help me sync files/data with my server such that if some file/data is changed on a local computer it'll replicate itself in our server and if I change some file/data on my server, it'll update on those local computers whenever they get an internet connection.