Flatten user entity to a github account

[nikita715]

I can't logout from github for no reason. The button is inactive.

[tcibinan]

@nikita715 Thank you for creating the issue.

Currently, there is no implementation for github log out and the button itself is just a mock.

There are several reasons why it is so.

1. If user wants to log in with another github account then what does it mean in terms of courses? From my point of view, we should transform existing courses to a read-only state. But I can't tell is it an expected behavior or not.
2. Another issue is that codacy and travis tokens are linked to a single github account. Therefore, if user changes his github account then he has to change his codacy and travis tokens as well.

Probably, some kind of configurations can be of use here. Configuration can aggregate github+travis+codacy tokens into a single entity.

[nikita715]

As far as I understand, github account identifies solutions of each student. I think you should move github auth to the registry if there is no reason and no possibility to logout from it. Or maybe the registry should be done only via github to form the closest relation with account in your system.

[tcibinan]

It sounds reasonable. Moreover, Travis and Codacy have the same mechanism as you described. It will also make Bitbucket or GitLab integrations easier.

[tcibinan]

So the current implementation plan is the following:

• flatten user account structure removing username and password fields
• use github username wherever account username was used
• replace basic auth with jwt token auth