Ignore .bundle directory and .ruby-version file
Workaround for failing build on Ruby 1.8.7

* https://github.com/bundler/bundler/issues/2780
* https://github.com/bundler/bundler/issues/2784
* https://github.com/rspec/rspec-expectations/commit/d2e3d97e5f0f1e23061f26376d2a752292c2a5d2
Enable Ruby 2.0.0/Rails 3.2.0 build