How to use this ruby docker image

I am facing issue while using pipeline for ruby script. I have file the issue in bitbucket also, Issue #15542 https://bitbucket.org/site/master/issues/15542/pipeline-script-bundle-install-could-not.

Kindly find the pipeline configuration. getting error “Could not locate Gemfile”.

image: ruby:2.4.0
pipelines:
  default:
    - step:
        script:
          - ruby - v
          - bundle install

Kindly guide me on below issue