intridea/oauth2 — pull request #157 by Nielsomat (2013-11-21 18:14:11+00:00)
Title: Ruby 1.8 / 1.9 compat: mime-types >= 2 depends on Ruby >= 2

The README claims compatibility with Ruby < 2, but the newest coveralls by default pulls in mime-types v2 which is only compatible with Ruby >= 2. So I'd suggest pinning it to < 2, as done here.