no members added in the groups while i do groupadd

Whenver i create any user in the groups, We can check the /etc/grops file
whether it has been added or not.

But whenver i check the above file, i dont see members added in the group.
Please advise.

I do the following things:

[root@localhost ~]# groupadd hewit
[root@localhost ~]# vigr
vigr: no changes made
vigr: /etc/group unchanged
[root@localhost ~]# gpasswd hewit
Changing the password for group hewit
New Password:
Re-enter new password:
[root@localhost ~]# su - vipul
[vipul@localhost ~]$ newgrp hewit
Password:
[vipul@localhost ~]$ su - root
Password:
[root@localhost ~]# vigr
vigr: no changes made
vigr: /etc/group unchanged
[root@localhost ~]#

 Solution Givin By Group Members
  You means you want to add user vipul to  hewit group then give this cmd.

# usermod -G hewit vipul

and after check file /etc/group.

Tell me its working or not.