[CentOS] /etc/init.d CentOS 7

There is a README file on CentOS 7 in /etc/init.d
that says

Note that traditional init scripts continue to function on a systemd
system. An init script /etc/rc.d/init.d/foobar is implicitly mapped
into a service unit foobar.service during system initilization

So I dropped my file in the above directory, rebooted and my item did not
start.

doing "systemctl list-unit-files | grep myservice" did now show anything.

What piece did I miss?

I used to use rc.local and just need a script to run AFTER everything else
has ran.
no special start/stop/reload is needed... just a simple script.

Thanks

jerry