docs updates

docs/editing-this-site.md

@@ -0,0 +1,7 @@
+If you'd like to edit this website and test it locally:
+
+Per https://help.github.com/en/github/working-with-github-pages/testing-your-github-pages-site-locally-with-jekyll
+
+* follow instructions here: https://jekyllrb.com/docs/installation/ubuntu/
+* run "run-locally.sh"
+* view webpages at localhost:4000