feat(cl): add example for creating custom settings file

[florean]

There are file patterns for custom Django settings files in the .gitignore, but there are no examples or documentation for using them and it is not very discoverable. I added an example settings file with some documentation and a couple example settings that solve problems I have run into along with the corresponding line in the .env.dev.example file.

I also updated the wiki with documentation on using custom settings. Sorry, I thought it would create a PR or something, I did not know the changes would immediately go live. If this gets merged, it should be updated again (happy to do it).

[florean]

Sorry about the wiki edit. Do you have a process for that? I can't believe GitHub still doesn't allow PRs against them. I can already see that I left off the Add your problem here... line.

[mlissner]

Hm, thanks for doing this. I thought we could override settings just by tweaking values in the env file. I think you've got a solution that works, but it's sort of layered on top of the simpler solution we'd prefer. Did you try that?

[florean]

I haven't dug into the documentation, but my assumption with django-environ was that it only overrides settings that have an explicit env call. We could add that to AWS_S3_CUSTOM_DOMAIN, but that doesn't help for cases like in my examples, such as modifying the CSP or a setting that takes a function. Basically any settings more complicated than a boolean or string.

I created these because I needed to modify settings (literally the examples I've included), but that is a pain when switching branches often. So I spent some time figuring out how to use a custom Django settings file with the project's setup and the final step was adding it to the .gitignore, which is when I discovered there was already a rule that covered this scenario. I've got everything I need and maybe nobody else needs custom settings, but I thought I'd contribute what would have saved me the most time in case someone does. If you have a simpler system that handles my use cases, then I'm happy to add some documentation for it, because I don't know what it is.