void ChannelContactModel::setTextChannel(const Tp::TextChannelPtr &channel)
{
    //remove existing contacts in list
    beginRemoveRows(QModelIndex(), 0, m_contacts.size());
    m_contacts.clear();
    endRemoveRows();

    //add existing contacts from channel
    addContacts(channel->groupContacts());

    //monitor for future changes
    connect(channel.data(),
            SIGNAL(groupMembersChanged(Tp::Contacts,Tp::Contacts,Tp::Contacts,
                                       Tp::Contacts,Tp::Channel::GroupMemberChangeDetails)),
            SLOT(onGroupMembersChanged(Tp::Contacts,Tp::Contacts,Tp::Contacts,
                                     Tp::Contacts,Tp::Channel::GroupMemberChangeDetails)));
}