Local and Online Server DB Sync

I am building a application using(Django-Mysql-Vuejs) for a customer who have around 20 stores across the country the application needs to work even when the internet is not available. so we decided to deploy the application on each store setting up a local server. I have set the primary key on each table to make the data unique so it will not conflict between each store. Now the same application is deployed also in the cloud what i actually need to do is i need to move all the data in each store to cloud database so that the management team can view all the data at a single database.