Has anyone done OAuth using Slack for User Logins?

I'm investigating whether I can use my Slack accounts as the primary login, and then have the system authenticate people based on their inclusion in a Slack group. Has anyone used Slack for OAuth using Jumpstart? 

We're using Slack OAuth for https://unicorntrain.com/ - which took some effort to implement. The standard omniauth-slack gem is quite dated and only supports the V1 OAuth flow, which may be fine based on your requirements.

For the latest V2 flow, you'll need a fork of this gem such as:

gem 'omniauth-slack', github: "teamspaces/omniauth-slack", require:'omniauth-slack'

In the lib/jumpstart/lib/jumpstart/omniauth.rb file, you also need to add a new value to the AVAILABLE_PROVIDERS:

"slack" => {name: "Slack", scope: "identity.basic,identity.email,identity.avatar", provider: :slack, icon: :slack}

Then from the Jumpstart admin config, you can enable Slack as a provider and add your Slack API credentials (https://jumpstartrails.com/docs/credentials) I hope that helps!