Using a local DNS with OpenVpn

I’ve been using FreedomBox on a local Debian system primarily as a VPN
so to access my internal network while traveling. I had to add
‘push “route”’ to /etc/openvpn/server/freedombox.conf
so that I could use the local names using my local DNS.
Last (automatic) update of FreedomBox overlayed the freedombox.conf and
lost the push statement.

How should I have set up OpenVpn so that it always uses my local DNS first?