This is something I have to do from time to time, but not frequently enough that I manage to memorize it - but trivial enough that it annoys me to have to look it up every time.
Here's to future memory:
- create a new user `bob`
sudo adduser bob
- check that the `admin` group is the one for the 'sudoers' on the machine
sudo cat /etc/sudoers
- add Bob to the admin group
sudo addgroup bob admin
done!