Function create_backup_version 

pub fn create_backup_version(
    conn: &Connection,
    user_id: i64,
    algorithm: &str,
    auth_data: &str,
    now: &str,
) -> Result<i64>

Create a brand-new key-backup version — a version number is never reused (soft-delete only, see delete_backup_version), so this is a plain insert.