The only way that
/etc/resolv.conf gets changed is if you're running
dhclient(8) on a network interface.. the client will populate the file with a nameserver offered by a dhcp daemon/server.. either your own or your ISP's.
You can create a file called
/etc/resolv.conf.tail and add your own additional settings, but to supersede the information from dhcp you need to instruct the client to do so.
To do this you'll need to edit
/etc/dhclient.conf, you can add simply:
supersede domain-name-servers 127.0.0.1;
But you may wish to read more about the other options available to you, see
dhclient.conf(5).