The best way if you’re running as root, is to drop a file into /etc/cron.d
if you use a package manager to package your software, you can simply lay down files in that directory and they are interpreted as if they were crontabs, but with an extra field for the username, e.g.:
Filename: /etc/cron.d/per_minute
Content:
* * * * * root /bin/sh /home/root/script.sh