code: func (r *RoleBindingBuilder) Users(users ...string) *RoleBindingBuilder {
  	for _, user := range users {
  		r.RoleBinding.Subjects = append(r.RoleBinding.Subjects, Subject{Kind: UserKind, APIGroup: GroupName, Name: user})
  	}
  	return r
  }
docs: // Users adds the specified users as the subjects of the RoleBinding.