box: wercker/ruby
service:
    - wercker/redis
build:
    steps:
        - bundle-install
        - script:
            name: Run rspec
            code: bundle exec rspec

box: wercker/rvm
service:
    - wercker/redis
build:
    steps:
        - rvm-use:
            version: 2.2.0

        - bundle-install
        - script:
            name: Run rspec
            code: bundle exec rspec

Use rvm with ruby 2.2.0
Use rvm with ruby 2.2.0
