title: Multiple apps in our parse-server
body: <p>Given that there's a solution for running multiple apps (here: <a href="https://github.com/parse-community/parse-server/issues/1979" rel="nofollow noreferrer">https://github.com/parse-community/parse-server/issues/1979</a>)  in one parse-server, what would be the approach to migrate existing data from multiple parse servers while keeping the ids and other relations, etc. intact?  </p>