When should a build run? - **Idea 1**: run the build on every push (PR + master) - **Idea 2**: run the build when asked, eg like Google [does](https://github.com/GoogleCloudPlatform/marketplace-k8s-app-tools/pull/333#issuecomment-476383364) with `/gcbrun` Where should the build run? - **Idea A**: Github Actions which in turn will run `gcloud builds submit`
