I added a user using useradd
useradd -g upperdevs myuser
But when I do an id check I didn't see the upperdevs group.
id myuser #uid=1000(myuser) gid=1000(myuser) groups=1000(myuser),27(sudo)
Probably this was the issue why I can't write to certain_dir, by doing
drwxrwxr-x 2 root upperdevs 4096 Sep 8 13:35 certain_dir
Anything I'm doing wrong?