Updating application config to use rspec

Each Rails application can specify which Framework is used. By default
the Hydra stack uses RSpec.
Writing executable tests for capybara tests
Manually adding jettywrapper gem
Installing, via bundler, the jettywrapper gem

Commands:
$ bundle
Updating documentation with testing philosophy
Manually adding active-fedora gem

This is included in the hydra-head gem, but I want to reference the
newer ActiveFedora::Base generators.
Updating, via bundler, the active-fedora gem

Commands:
$ bundle update active-fedora
Adding Thing model and corresponding spec

Script
$ rails generate active_fedora:model Thing
Updating README to include how to run tests
Changing README from rdoc to markdown

Personally, Markdown is so much more legible.