users.go
func (client *Client) InviteUsers(emails []string) error {
	return client.doJsonRequest("POST", "/v1/invite_users",
		reqInviteUsers{Emails: emails}, nil)
}
func (client *Client) InviteUsers(emails []string) error {
	return client.doJsonRequest("POST", "/v1/invite_users",
		reqInviteUsers{Emails: emails}, nil)
}
// InviteUsers takes a slice of email addresses and sends invitations to them.