Read closely and you'll see the answers in the link: Yes. "it is possible to inject some environment variables into gerve" Because it's his git hub username.

Read closely and you'll see the answers in the link: Yes. "it is possible to inject some environment variables into gerve" Because it's his git hub username. You answered that question yourself: "And what username is being set - ssh? github account? wouldn't you need to use exactly the username 'git' when ssh'ing in to github to trigger this gerve app anyways?" So if it's not his ssh username it must be his... 'github username'! it's the only other possibility you could think of right? ...