API Query channel members

Hi @tht13. The current api to do that is /api/v1/channels/<CHANNEL_ID>/extra_info/<LIMIT>. From that, you'll get a json blob of the form

{
    id: CHANNEL_ID,
    members: A list of up to LIMIT truncated User objects with user id, nickname, email, and username
    member_count: The number of members in the channel including those not returned due to the limit
}

I believe that a limit of -1 will also cause the system to give you all members of that channel, but I'm not 100% certain of that.