Speed up your Ruby CI builds on Travis

Tired of installing gems on every build? Travis CI introduced a way to cache directories between builds. We can use this feature to cache gems installed from Bundler. Take a look at the following .travis.yml:

language: ruby

cache:
  bundler: true

More information about this time saving feature here. It cut our build time by 50-75%.

Note: This feature is currenly only available on Travis Pro.