User registration: ask user to provide email if it cannot be retrieved from Github

[carpodaster]

Users can mark their email address private on their Github profile, making it unavailable for API clients like the one retrieving user data by github handle when a user registers in our site.

If the registration process cannot complete with a valid email address, redirect the user to a form and ask them to provide one.

Note: this may already be implement. Investigate first.

[hola-soy-milk]

I've done some research and come to some conclusions:

1. You cannot Oauth on a fresh Github account without a verified email address:
   

2. Marking an email address as private still allows this to be imported by the Oauth app

3. Creating a new account takes the new user to complete their profile.

Given this information, what do you think? I'd almost say that, given the above, we can leave it as is.

[klappradla]

Oh wow @ramonh 🙇

That's ace! Means the problem of not being able to retrieve an email address actually does not exist at all?

When and under which circumstances was this then originally reported @carpodaster ?

[carpodaster]

Great find, Ramon! 🕵️‍♂️

Maybe it wasn't always the case? I'm pretty we've had reports by orga people that users on the Teams App hat their email address set to nil 🤷‍♂️ I'm closing this.

[emcoding]

When I start a new team, I can add team members that don't exist: partyppooper, or that have a hidden email address: Sandi Metz skmetz.
In both cases we store a user with email address: nil

I know I did something like this for real, when I didn't know Roos yet and I wanted to see what the application form was like. So, it's not a hypothetical case.
Do we (need to) get rid of the fake users?

[hola-soy-milk]

Ahh! Good point, @F3PiX. I overlooked adding team members. Maybe we should reopen this, huh?

[emcoding]

Well, I don't know by heart what happens when a user added by team members sign in with Gh the first time. (See conv in Slack, I am working on sketching the flow.)
Maybe it is a different issue alltogether - related to cleaning up the database?

[emcoding]

Definitively reopen
Reproduce:

• Make yourself a team member on the website
• Add a fake name, for a non existing user (like partypppooper)
• On the teampage, click on the newly create team members name/github link. => 404
  It is not a valid github name, but is added to our database and as a team member.

In console, check out User.last. See that non of the github fields are populated, except for the fake handle.

• We use find_or_create_by_github_handle to create a new user. I'd like to investigate if we could change that to github_id, to catch invalid entries.
  TBD later, adding it to the list for User Registration Overhaul: break down #991