middleman/middleman-guides — pull request #169 by tricknotes (2013-03-21 17:55:51+00:00)
Title: Replace `source :rubygems` with url for rubygems.org

Bundler (>= 1.3.0) says:
```
The source :rubygems is deprecated because HTTP requests are insecure.
Please change your source to 'https://rubygems.org' if possible, or 'http://rubygems.org' if not.
```