code: function figureOutWhoUserIs(req) {
        // just stubbing this out here
        var username = req.query.username
        if (username === 'skroob') {
          return {
            username: username,
            email: 'pres@skroob.com'
          }
        }
        throw new HttpErrors.Unauthorized()
      }
docs: post-authentication-customAuthHeader