Adds a member to an existing group. The member can be an individual
 principal, a collection of principals denoted with wildcards, or
 another group. Use the optional keywords as group to specify that
 the member you are adding is itself a group. If you omit this
 argument, the principal is not a group.

 SYNOPSIS

      ADD GROUP group-name MEMBER [=] principal [AS GROUP]

 Arguments

 group-name

 The full name of the group.

 principal

 The principal that is being added as a member of the group. You
 can specify a principal as a group name, a collection of principals
 denoted with wildcards (for example, .org.name*), or an individual
 name in the format, nodename.username. To specify a DNS Version 1-style
 principal, use the format nodename::username. The phrase as group
 indicates the specified principal is itself a group. You cannot use
 this phrase with wildcard principal names.

 ACCESS RIGHTS
 You must have write access to the group to which you are adding a
 member.