ok = peer:stop(P).
multi_channel_membership_test() ->
    A = make_test_args(),
    {ok, P} = peer:start_link(A),
    {ok, PubKey} = peer:node_public_key(P),
    %% Join Channel A
    peer:join(P, "ChannelA"),
    {ok, MembersA} = peer:channel_members(P, "ChannelA"),
    MembersMapA = proplists:get_value(members, MembersA),
    ?assert(maps:is_key(PubKey, MembersMapA)),
    %% Join Channel B
    peer:join(P, "ChannelB"),
    {ok, MembersB} = peer:channel_members(P, "ChannelB"),
    MembersMapB = proplists:get_value(members, MembersB),
    ?assert(maps:is_key(PubKey, MembersMapB)),
    %% Verify still in Channel A
    {ok, MembersA2} = peer:channel_members(P, "ChannelA"),
    MembersMapA2 = proplists:get_value(members, MembersA2),
    ?assert(maps:is_key(PubKey, MembersMapA2)),

                    "ON CONFLICT(user_id) DO UPDATE SET last_hash=excluded.last_hash",

                    "ON CONFLICT(channel, user_id) DO UPDATE SET last_hash=excluded.last_hash",

create table IF NOT EXISTS channel_members (
    id integer primary key AUTOINCREMENT,
    channel text not null,
    user_id integer not null,
    last_hash blob not null,
    UNIQUE(channel, user_id)
);

        channel_members => [
            ColId,
            {channel, text, not_null},
            {user_id, integer, [unique, not_null]},
            {last_hash, blob, not_null}
        ],