Code considerably out of sync with the videos

[this-josh]

The code in this repo is considerably different to what is mentioned within the videos, with the video code sometimes having more detail and this repo sometimes having more detail. For a stark example please compare this repo's factorisation code against the factorisation video, although this issue is present throughout the course. I appreciate wanting to update this repo, but it would be good if the course linked to a specific commit/tag. Also, I'd expect this repo to be ahead of the video and therefore not missing any content.