useradd does not add new group for newly added user

Issue

useradd does not add new group for newly added user

• User was added without specifying any parameter:

  # useradd bob
  

• When adding new user accounts, no new group was created.

• The new user account was created with primary group gid=100(users)

  # id bob
  uid=1002(bob) gid=100(users) groups=100(users)
  

• Below log message has been recorded in /var/log/secure:

  useradd[34648]: new user: name=bob, UID=1002, GID=100, home=/home/bob, shell=/bin/bash