Make sure that `gem install eventmachine -v '1.2.7' --source 'http://rubygems.org/'` succeeds before bundling.
In Gemfile: jekyll-sitemap was resolved to 1.3.1, which depends on jekyll was resolved to 3.8.5, which depends on em-websocket was resolved to 0.5.1, which depends on eventmachine ERROR: Job failed: exit code 5
