Ignore Gemfile.lock
add Appraisal support
Remove dummy app's Gemfile & Gemfile.lock
Appraisal for Rails 3.1

 * add Rails 3.1. gemfile
 * better Rails version tests
 * use Strings instead of named routes in tests to support running on
   Rails 3.1
Gemfile: use https://bundler-api.herokuapp.com
Update FactoryGirl to 4.2

 * update factory definitions
 * mix FactoryGirl::Syntax::Methods into tests
 * Factory(:feature) -> create(:feature)
Rails 4.0.0.beta1 support

 * add rails4-0 Appraisal
 * ActiveRecord::Base#initialize takes only one argument in Rails 4
 * extract FeaturesController#feature_params and #features_params
   to do StrongParameters checking
 * don't set config.whiny_nils in dummy app on Rails 4 since it's
   deprecated
 * set config.eager_load in dummy app on Rails 4
 * use ActionDispatch::IntegrationTest instead of
   ActionController::IntegrationTest on Rails 4