Most likely you do not need to do that. If you type
id you can see what groups you are in:
Oh look I am in a group called
sudo... that means I am allowed to issue commands as the superuser... which commands am I allowed to use in that way?
$ sudo -l
User zanna may run the following commands on monster:
(ALL : ALL) ALL
That's probably enough privileges :)
Here's a good question about managing users and groups in Ubuntu as pointed out by Anwar Shah. The Arch wiki also gives insight.