write $GH_CNAME to CNAME before commiting

[bennypowers]

closes #12

[maxheld83]

ah yes, I had forgotten about this pesky detail. Thanks for this!

• I was planning on adding some testing here first, and then merge your PR, if it's not too urgent. I think we should then also test whether CNAME deployment works.

• Also as a convenience, I think it might be nice to point users to a bit more docs on ghpages + CNAME file (conspicously hard to come by at github docs ...):

  • https://ouyi.github.io/post/2018/01/14/github-pages-cname-file.html
  • https://help.github.com/en/articles/troubleshooting-custom-domains#github-repository-setup-errors
  • ...

• and lastly: do you have any thoughts on whether this should be an environment variable or argument? I was thinking, since it changes behavior, it should maybe be an argument as per usual bash logic? Maybe make build_dir an argument, too, while we're at it? (though that one *doesn't' change behavior).

[bennypowers]

Agree about testing and args. I found a workaround to tide me over in the mean time (spoiler alert: it's a storybook site, so I added the CNAME to the storybook-static dir).

Thanks.