--- a/Gemfile	Mon Jul 20 16:14:52 2020 +0900
+++ b/Gemfile	Thu Sep 10 17:47:36 2020 +0900
@@ -1,33 +1,3 @@
 source "https://rubygems.org"
 
-# Hello! This is where you manage which Jekyll version is used to run.
-# When you want to use a different version, change it below, save the
-# file and run `bundle install`. Run Jekyll with `bundle exec`, like so:
-#
-#     bundle exec jekyll serve
-#
-# This will help ensure the proper Jekyll version is running.
-# Happy Jekylling!
-
-# NOTE: Jekyll 4 released 2020-05-09, but no support for Pygments, see below
-#       https://jekyllrb.com/docs/liquid/tags/
-gem "jekyll", "~> 3.8.7" # Release 2020-05-08
-
-# If you have any plugins, put them here!
-group :jekyll_plugins do
-  gem "jekyll-feed", "~> 0.14" # Release 2020-06-24
-end
-
-# Rouge is the default highlighter for Jekyll 4 and does not support Octave
-# highlighting yet.  Thus stay on Jekyll 3.8 for a while.
-gem "pygments.rb"
-
-# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
-# and associated library.
-install_if -> { RUBY_PLATFORM =~ %r!mingw|mswin|java! } do
-  gem "tzinfo", "~> 1.2"
-  gem "tzinfo-data"
-end
-
-# Performance-booster for watching directories on Windows
-gem "wdm", "~> 0.1.0", :install_if => Gem.win_platform?
+gem "github-pages"