Ruby example fails to start.

[DanielJoyce]

latest: digest: sha256:4916f24ae6e371c929207e86cd6de1548c887fe2b1257cabf254e9cad0a3fa0b size: 3038
DONE
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Updating service [derp] (this may take several minutes)...failed.                                                                                                                           
ERROR: (gcloud.app.deploy) Error Response: [4] Your deployment has failed to become healthy in the allotted time and therefore was rolled back. If you believe this was an error, try adjusting the 'app_start_timeout_sec' setting in the 'readiness_check' section.

Does it really work without a CMD in the docker file?

[DanielJoyce]

Adding the following

CMD ["bundle", "exec", "ruby", "app.rb"]

to the ruby example allows it to start

[dazuma]

We also need to move off of the unsupported gcr.io/google-appengine/ruby base image, and onto a usable base image such as one of the official Ruby images from dockerhub.