data backup

[jmvanel]

Save the user data (not the cache) in Quads format, everyday at 3am local time.

Implementation:

• either in the server,
• or in a external process launching SPARQL queries
• anyway, need to get a list of users

Either

• ensure that the database is still running well (how?) before overwriting the backup,
• or keep a week of backups

[jmvanel]

Take inspiration from the Fuseki Backup service https://jena.apache.org/documentation/fuseki2/fuseki-server-protocol.html