Slack Integration using unmaintained passport-slack

[vevinkirk]

If you attempt to setup the slack integration you will be met with the error json is undefined due to the project passport-slack no longer being maintained. There is a new project that can be used or there is a fix to use profile instead. mjpearson/passport-slack#31

[vevinkirk]

The fix for this requires using the package https://github.com/nmaves/passport-slack-oauth2 and updating auth.js to use new package and update references to 'slack' to be 'Slack' will follow up with pull request to fix issue