SIMULATION
According the following requirements to create user, user group and the group members:
- A group named admin.
- A user named mary, and belong to admin as the secondary group.
- A user named alice, and belong to admin as the secondary group.
- A user named bobby, bobby's login shell should be non-interactive. Bobby not belong to admin as the secondary group.
Mary, Alice, bobby users must be set "password" as the user's password.