This is exactly the same as https://github.com/greyltc/docker-archlinux with the following exception:
Containers based on this one can use the following to install PACKAGE from the AUR:
su docker -c 'yay -S --noprogressbar --needed --noconfirm PACKAGE'So in your Dockerfile, that would look like:
RUN su docker -c 'yay -S --noprogressbar --needed --noconfirm PACKAGE'