I had some problems testing out this branch.  It seems like the usage of the GITHUB_ENTERPRISE_URL is inconsistent.  For example in this file "team_access?" will only work properly if GITHUB_ENTERPRISE_URL is in the form "http(s)://<your enterprise domain>/api/v3", but "destroy" will only work if GITHUB_ENTERPRISE_URL is in the form "http(s)://<your enterprise domain>".  There are similar inconsistencies elsewhere.

I put together a pull request for your branch that fixed the problems for me: https://github.com/j-wilkins/boxen-web/pull/2