rvm:
  - 1.9.3
  - 2.0.0
  - 2.1.0
script: bundle exec rspec

rvm:
  - 1.9.3
  - 2.0.0
  - 2.1.0
script: bundle exec rspec
sudo: false

Use Travis container-based infrastructure, cache bundler
Use Travis container-based infrastructure, cache bundler

This new infrastructure "promises short to nonexistent queue wait times,
as well as offering better performance for most use cases." According to
their documentation[0], we can opt in by adding `sudo: false` to our
.travis.yml config file.

This also allows us to cache installed gems[1], which should speed up
the Travis builds even more.

[0]: http://docs.travis-ci.com/user/workers/container-based-infrastructure/
[1]:
http://docs.travis-ci.com/user/caching/#Caching-directories-(Bundler%2C-dependencies)

Change-Id: I2d56e2e0423680be8730bf738841f070fe15315f
