The "popular" answer is how to "reimplement", not "how to add the user?". Bare minimum you need to do is this:

usermod -a -G sudo USERNAME

On my particular system, I am a member of the following groups:

usermod -a -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,libvirtd USERNAME

The "popular" answer is how to "reimplement", not "how to add the user?". Bare minimum you need to do is this:

usermod -a -G sudo USERNAME

On my particular system, I am a member of the following groups:

usermod -a -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,libvirtd USERNAME

To verify what you have done:

groups USERNAME

The "popular" answer is how to reimplement, not how to add the user. Bare minimum you need to do is this: usermod -a -G sudo USERNAME

On my particular system, I am a member of the following groups.

usermod -a -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,libvirtd USERNAME

The "popular" answer is how to "reimplement", not "how to add the user?". Bare minimum you need to do is this:

usermod -a -G sudo USERNAME

On my particular system, I am a member of the following groups:

usermod -a -G adm,cdrom,sudo,dip,plugdev,lpadmin,sambashare,libvirtd USERNAME