use edge until 4.0 is released
rdoc is no longer a gem dependency, sdoc becomes a runtime dependency
encrypted_cookie_store option was removed. Use cookie_store instead
Update the call to Bundler.require in application.rb
Mention that debugging can be slow.
fix sentence
config.ru uses the effective Rack app
Make sure that `rails test` load test in test env
Remove extra whitespace and fix a comment
improve error pages