Follow GitHub set up tutorial steps

https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/creating-a-github-pages-site-with-jekyll

.gitignore

@@ -3,3 +3,6 @@ _site
 .jekyll-cache
 .jekyll-metadata
 vendor
+
+# https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/creating-a-github-pages-site-with-jekyll
+Gemfile.lock

Gemfile

@@ -5,9 +5,14 @@ source "https://rubygems.org"
 #
 #     bundle exec jekyll serve
 #
+# Check github pages versions here: https://pages.github.com/versions/
+#
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem "jekyll", "~> 4.3.4"
+# NB: github pages own advice to comment this out:
+# https://docs.github.com/en/pages/setting-up-a-github-pages-site-with-jekyll/creating-a-github-pages-site-with-jekyll
+# gem "jekyll", "~> 4.3.4"
+
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
 gem "minima", "~> 2.5"
 # If you want to use GitHub Pages, remove the "gem "jekyll"" above and
@@ -16,6 +21,7 @@ gem "minima", "~> 2.5"
 # If you have any plugins, put them here!
 group :jekyll_plugins do
   gem "jekyll-feed", "~> 0.12"
+  gem "github-pages", "~> 232"
 end
 
 # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem