Problems deploying demo by following step-by-step guide

Hi guys,
first of all thanks a lot for providing this demo and for the detailed explanations on Medium. I tried to set everything up as described by the step by step guide and run into some problems. I've documented them, maybe you can update the guide on Medium accordingly:

- gcloud builds submit -config cloudbuild.yaml doesnt work any more - I simply used gcloud build submit
- the steps in cloudbuild.yaml are wrong numerated in the comments. Should start with 0 and not 1, like in the gcp console. Can be confusing for beginners.
- firebase_config.json needs to be in folder cloudbuild for #step 0 to work
- Cloudbuild service account needs to have the App Engine Deployer Role to successfully deploy the app in step 2 of the build
- Cloudbuild service account needs to have the App Service Admin role to successfully promote the new version as default in step 2 of the build
- Cloudbuild service account needs to have the Cloud Functions Developer role to successfully deploy the function in step 4 of the build
- Cloudbuild service account needs to have the serviceAccountUser role for step 4 of the build
- set timeout to 900s for the whole build in cloudbuild.yaml file - otherwise we might run into timeouts with the build
- we don't need to whitelist our domain in Firebase, but also activate the Google Signin provider
- the upload image url in static/enableFilepond.js needs to be adjusted

Start with the step-by-step guide, then compare its instructions with cloudbuild.yaml, firebase_config.json, and static/enableFilepond.js. Verify each listed deployment, permission, timeout, Firebase, and upload-URL issue against the current Google Cloud setup. Done means the guide and referenced files consistently describe a deployable demo for beginners.

Written by the indexing model from the issue text.