Per this question,I decide to create dummy user to be the owner of website files.
Centos 7 offer default group ID 100 when I run
useradd -u 508 -M -N -s /sbin/nologin dummyuser1.
I want to provide as little as possible privilege to the
dummyuser1,then I don't want
dummyuser1 has group.
How to do it?