Add a FAQ for GHCR.

Addresses the questions from #3.

Signed-off-by: Chad Metcalf <[email protected]>

Author: metcalfc

README.md

@@ -6,6 +6,8 @@ Welcome. This is a simple example application to show a common Docker specific
 GitHub Action setup. We have a Python Flask application that is built and
 deployed in Docker containers using Dockerfiles and Docker Compose.
 
+## CI Setup
+
 We want to setup CI to test:
 
 - ✒ [Every commit to `main`](https://github.com/metcalfc/docker-action-examples/blob/main/.github/workflows/main-ci.yml)
@@ -46,6 +48,38 @@ I'm not going to have GitHub Action manage the deployment side of this example.
 Mostly because I don't want to leave an Amazon ECS cluster running. But you can
 see a demo of this in one of my past streams: https://www.youtube.com/watch?v=RfQrgZFq_P0
 
+## GitHub Container Registry FAQ
+
+### Where does this `secret.GHCR_TOKEN` come from?
+
+The secret isn't automatically populated. The original GitHub Packages container registry did use the automatically generated `GITHUB_TOKEN`. GitHub has said that support for that will be added to this new registry in the future.
+
+<br>
+
+<blockquote class="twitter-tweet"><p lang="en" dir="ltr">Support for Actions through GITHUB_TOKEN is coming.</p>&mdash; Bryan Clark (@clarkbw) <a href="https://twitter.com/clarkbw/status/1300853015113396225?ref_src=twsrc%5Etfw">September 1, 2020</a></blockquote>
+
+<br>
+
+For now you will need to create a GitHub Personal Access Token (PAT) which you can do by going here: https://github.com/settings/tokens
+
+You'll need to create the PAT with the correct scopes which you can find here: https://docs.github.com/en/packages/getting-started-with-github-container-registry/migrating-to-github-container-registry-for-docker-images#authenticating-with-the-container-registry
+
+Once you have the PAT you can create an action secret: https://docs.github.com/en/actions/configuring-and-managing-workflows/creating-and-storing-encrypted-secrets
+
+You can call the secret whatever you want. But `GHCR_TOKEN` is what I used for the example above.
+
+### I thought GHRC had anonymous pulls?
+
+Its a beta product so the documentation doesn't really exist yet. If you dig around on
+[GitHub's Community site](https://github.community/tag/ghcr) you can find some answers.
+Thats a pain so here is what I've found.
+
+`ghcr.io` is private by default. You'll notice in the [nightly.yml](.github/workflows/nightly.yml) I had to do a login to be able to pull the image.
+
+You can see what packages you have by going here (change the username): https://github.com/USERNAME?tab=packages&visibility=private
+
+You can make it public going to the packages settings (change the username and project name): https://github.com/users/USERNAME/packages/container/PROJECTNAME/settings
+
 ## Compose sample application
 
 ### Python/Flask application