Copy the sample apps to your local machine, and cd to the storage directory:

git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples
cd ruby-docs-samples/appengine/standard-storage

Make sure gcloud is installed and authenticated. You can find your project id with gcloud config list.

Create a Cloud Storage bucket for your project:

$ gcloud storage buckets create gs://<your-project-id>

export GOOGLE_CLOUD_PROJECT=<your-project-id>
export GOOGLE_CLOUD_STORAGE_BUCKET=<your-project-id>
bundle
bundle exec ruby app.rb

Visit on http://localhost:4567/

Choose a file and click "Upload".

The public URL to the uploaded file will be displayed.

Replace <your-project-id> and <your-bucket-name> in app.yaml, then:

gcloud app deploy

Note: the tests do a live deploy to App Engine

Put a client_secrets.json file for a service account in the root of your repo.

gcloud auth activate-service-account --key-file ../../client_secrets.json
export GOOGLE_CLOUD_PROJECT=<your-project-id>
export TEST_DIR=appengine/storage/
bundle exec rspec