Figure out how to forward GitHUb credentials

[jamesaoverton]

Related to #45, there are cases where we want to run a script as a user with GitHub authentication. It would solve a lot of problems.

I think it would be simple to expose the user token to the branch environment. But it sounds dangerous. We need to give it some serious thought.

[lmcmicu]

#45 relates to CGI scripts. In this case are we speaking of more general kinds of scripts that would be run by DROID?

[jamesaoverton]

Now I think that both issues should be general: CGI scripts and Makefile tasks, and scripts that Make calls, etc,