Fix page build failures

Hey Erik,

I think that this pull request will fix the page build failures on your site. To make a long story short, https://github.com/jekyll/jekyll-redirect-from/pull/26 and https://github.com/github/pages-gem/pull/88 were recently merged, and as a result the `jekyll-redirect-from` gem now makes the assumption that `site.github.url` will always be used as a redirect prefix. You had a different value for `site.github` in your *_config.yml*, which likely confused the gem.

If this does indeed fix your problem and you're interested in discussing the effects of the recent changes further, check out https://github.com/jekyll/jekyll-redirect-from/issues/42.

Hope this helps! :heart: :octocat: