Rails 4 includes strong parameters and removed attr_accessible
(protected attributes). I removed the strong_parameters development
dependency and added it to all non-4.0 appraisals. I also added the
'protected_attributes' gem to the 4.0 appraisal because the test suite
examples make heavy use of attr_accessible.
> Use a pessimistic version in the Gemfile for gems that follow semantic
> versioning, such as rspec, factory_girl, and capybara.
https://github.com/thoughtbot/guides/tree/master/best-practices
* Upgrade dependencies so specs run on new Bourne.
* Use semantic versions in step_definitions gems.
* Rely on ActiveSupport::Dependencies.clear for reloading constants.
http://rkh.im/code-reloading
