machine:
  node:
    version: "stable"
dependencies:
  pre:
    - npm install -g bower
  post:
    - bower install


machine:
  node:
    version: "stable"
dependencies:
  pre:
    # <Yarn>
    - sudo apt-key adv --fetch-keys http://dl.yarnpkg.com/debian/pubkey.gpg
    - echo "deb http://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
    - sudo apt-get update -qq
    - sudo apt-get install -y -qq yarn
    # </Yarn>
  cache_directories:
    - ~/.yarn-cache
  override:
    - yarn global add bower --no-progress
    - yarn install --no-progress
    - bower install

Update Circle config to use Yarn
Update Circle config to use Yarn
