Creating a passport strategy from user data from another node application (for NodeBB)

I've looked this up on Google to no avail.

I want to create a Passport strategy so users from my other node.js app can log in instantly to nodebb, but I haven't seen this working in action. I believe I should request the log in details from the other app.

I can't use oauth because this is for an internal forum and I only want to allow certain members of staff access to it.

What I believe should happen is this:

1. The user should use the link from the other application to the NodeBB forum.
2. The NodeBB forum, using passport, should request the details from the other app or, if they are not logged in, redirect them to the other app, which in turn redirects back to the forum.
3. If they haven't used the forum before, then they should go through the user wizard.
4. Their user for the forum is saved on to the forum redis and the forum should handle the rest.

Is that correct? How do I go on about doing this?