[inaka/elvis-server#19] Teams GitHub API calls.
[inaka/elvis-server#19] Single user and repo info GitHub API calls.
[inaka/elvis-server#19] Add repo to team GitHub API call.
Merge pull request #73 from inaka/jfacorro.19.add.user.to.org.team

[inaka/elvis-server#19] Add user to Services team.