让 capybara 通过 selenium 运行所有rspec 测试用例
rspec2 selenium ，capybara 默认配置下只会运行一个it 测试用例，要想让 capybara 通过selenium 运行所有测试用例，(
make Capybara run all your tests in Selenium by setting)则需在 spec/spec_helper.rb 中设置：
2.
see:
http://www.opinionatedprogrammer.com/2011/02/capybara-and-selenium-with-rspec-and-rails-3/
https://github.com/jnicklas/capybara
