Setup slackin, or something, to invite people to the #halp channel

[aboodman]

Right now in the walkthroughs I've included a Slack "Shared Invite" because it's easy and reliable.

However there's no way to customize these invites to cause the resulting users to be "Single-channel guests", which is what we'd want ideally.

Probably we need to setup Slackin or something like it to generate invites:

https://www.quora.com/Is-there-a-way-to-enable-anyone-to-join-a-Slack

[aboodman]

We decided not to do this, created a private channel instead.