Add GitHub action that publishes updated website when pushing to each pull request

[teodutu]

Building the website locally is tedious, takes a very long time, and 20GB+ of disk space. This makes it difficult to test changes to the documentation.

The solution is to add a GitHub action triggered by a new commit to a PR that runs the builder, publishes the rendered content, and then adds a comment to the PR containing a link to the published website that contains the changes within the PR. You can draw inspiration from the GitHub action used by the OS Internals class. An example of a comment created by this action is linux-kernel-labs/linux#316 (comment).

Ideally, this action would only be triggered by changes to the Markdown documentation or quizzes and not just code. For this, PRs should first be labelled automatically as per #89. According to this issue, the action should only be executed when the area/documentation label is present.

[razvand]

20GB+ of space? Are you sure? It didn't take that much on my side:

$ docker image ls
[...]
operating-systems-oer/docusaurus             latest          ba0f68a891a8   9 hours ago    1.27GB
[...]
ghcr.io/open-education-hub/openedu_builder   0.3.1           cadf3526a0e9   2 months ago   130MB
[...]

[teodutu]

20GB+ of space? Are you sure? It didn't take that much on my side:

I'm not sure why. Perhaps some of it is boilerplate files or something. What's certain is that the size of /var/lib/docker/overlay2 increased by 20GB+ when running the builder locally as described in https://github.com/open-education-hub/oer-template#running-locally.

[gabrielmocanu]

I don't have this issue related to disk space, but indeed building website locally is tedious.
After following all the steps from oer-template. This is what I got.
This needs to be solved first, at least to be able to build it locally.

[teodutu]

Change the name of the output/ directory to operating-systems/ and start the python3 server one level above this folder. Then it will work.