App Spec docs give no indication how to create them
This page needs more info how to create the App Spec file. I found out later it is possible to use
doctl apps spec validate, and
doctl apps --spec file.yaml --upsertcan be used to create/update the app, and
doctl apps propose --spec file.yaml.
Also the relation (or lack of) with the conventional paths of
.do/deploy.template.yamlshould be explained.
In my case the online UI didn't allow to detect my Dockerfile in specific location and had to use the app spec to define it. But I had very little clues on how to define the file.