Adding support for Macs with Apple Silicon chips

[drw]

I've run through these instructions to test them and offer some suggestions for improvements.

1] I got hung up on a few places because I was using a MacBook running an M1 chip. In the Ubuntu VM Setup section, the suggested virtualization solution (VirtualBox) didn't work. Joel suggested VMWare Fusion Pro, and I did eventually get this to work.

2] A few notes that you could include about this option: VMWare Fusion Pro (free for home use) can be downloaded by registering for a broadcom.com account and then going to this URL: https://support.broadcom.com/group/ecx/productdownloads?subfamily=VMware%20Fusion&freeDownloads=true

(I mention the download URL because the broadcom.com site has poor design, and the only way I found this download link was because someone had posted it to Reddit in response to a question.)

3] I couldn't paste text into the virtual machine, so shelling into the virtual machine from my terminal proved essential. Since this could benefit others, I recommend making this idea explicit with a line like

"If you're unable to paste text into the virtual machine, your options are to 1) search through the virtualization software settings and virtual machine configuration to figure out how to enable copying/pasting text or 2) just ssh into the virtual machine and then paste text into your terminal."

4] The postgis Docker image used in the CKAN set-up instructions has a long-running incompatibility with Apple Silicon chips. The problem is discussed in this GitHub issue.

The PostGIS code will compile on an ARM64 chip, but some problem with GitHub Actions prevents the Docker images from being reliably generated. Toward the bottom of that thread, two pull requests that could eventually solve this problem are mentioned, but basically now people either need to a) run the build on their own or b) use a community build.

I tried this community build (which was recommended somewhere among the GitHub issues).

To do this, I changed the first line of the postgres/Dockerfile from
FROM postgis/postgis:16-3.4-alpine
to
FROM imresamu/postgis:16-3.4-bundle0-bookworm

After that, running the instructions yielded a working CKAN instance for development in my virtual machine.