You’ll need to add the db file to your Dockerfile, then create a script that copies the file to /mnt/Database ( if it doesn’t already exist ) before it starts your app process. Something like this entrypoint should work.
COPY --from=builder Database.db /tmp/
if [ ! -f /mnt/Database/Database.db ]; then
cp /tmp/Database.db /mnt/Database/Database.db