Gemfile sources "https://rubygems.org" not :rubygems.

This fixes the following Bundler warning:

> 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.
multiple improvemnts to the README
edit the README for clarity
edit README
change dashboard in README
edit README
README shows how to include the css for the admin ui
Merge branch 'readme-improvements'
class 'flip' applies to the whole admin ui, not just the table.
indent using two spaces
tweak flip.css
Merge branch 'css-improvements'