Build: Publish theme as package

By publishing Amethyst as a package, and using it by name in individual
website repos (instead of by its raw Git repo URL), the dependencies
will be managed automatically, which should make it easier to get
started, and more importantly, easier to update.

(The initial start is equally easy as it involved copying the example
boilerplate, but the steps after that are less obvious).

.github/workflows/gem.yaml

@@ -0,0 +1,30 @@
+name: Gem
+on:
+  push:
+    tags:
+      - 'v*.*.*'
+
+jobs:
+  gem-push:
+    runs-on: ubuntu-latest
+    permissions:
+      # https://docs.github.com/en/actions/reference/authentication-in-a-workflow
+      packages: write
+    steps:
+    - uses: actions/checkout@v2
+    - name: Publish Gem package
+      env:
+        GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+      # Inspired by https://github.com/bodyshopbidsdotcom/gh-action-publish-gem-on-tag/blob/1.0.1/entrypoint.sh
+      run: |
+        GIT_VERSION=$(echo "$GITHUB_REF" | cut -d'/' -f 3-)
+        SPEC_VERSION=$(ruby -e 'require "rubygems"; gemspec = Dir.entries(".").find { |file| file =~ /.*\.gemspec/ }; spec = Gem::Specification::load(gemspec); puts spec.version')
+        if [[ "$GIT_VERSION" != "v${SPEC_VERSION}" ]]; then
+          echo "Ignoring, git tag version differs from gem spec version."
+          exit 2;
+        fi
+        mkdir -p ~/.gem
+        echo ":github: Bearer ${GITHUB_TOKEN}" > ~/.gem/credentials
+        chmod 600 ~/.gem/credentials
+        gem build *.gemspec
+        gem push --key github --host "https://rubygems.pkg.github.com/${{ github.repository_owner }}" *.gem

Gemfile

@@ -1,18 +1,6 @@
 source "https://rubygems.org"
 ruby RUBY_VERSION
 
-gem "jekyll", "~> 4.2.0"
-gem "kramdown-parser-gfm", "1.1.0"
-gem "jekyll-redirect-from", "~> 0.16.0", group: :jekyll_plugins
-gem "jekyll-relative-links", "~> 0.6.1", group: :jekyll_plugins
-gem "jekyll-remote-theme", "~> 0.4.3", group: :jekyll_plugins
+gemspec
 
-# Blog
-gem "jekyll-feed", "~> 0.15.1", group: :jekyll_plugins
-gem "jekyll-archives", "~> 2.2.1", group: :jekyll_plugins
-
-# Search
 gem "jekyll-algolia", "~> 1.7.0", group: :jekyll_plugins
-
-# Temporary fix until there is a release with https://github.com/jekyll/jekyll/pull/8524/
-gem "webrick", "~> 1.7"

README.md

@@ -22,13 +22,7 @@ Requirements:
 * [Ruby](https://www.ruby-lang.org/) (tested with Ruby 2.7+)
 * [Bundler](https://bundler.io/) (if missing, install with `gem install bundler`)
 
-To install Jekyll and plugins the first time:
-
-```shell
-bundle install
-```
-
-To update Jekyll and any plugins (e.g. after changing `Gemfile`):
+To install or update Jekyll and plugins:
 
 ```shell
 bundle update

_config.yml

@@ -19,15 +19,6 @@ baseurl: /jekyll-theme-amethyst
 permalink: /:year/:month/:day/:title/
 lang: en
 timezone: UTC
-# Disable theme inheritance since this repo contains its own theme top-level theme.
-# This isn't needed for plain Jekyll, but because we use github-pages as basis
-# we otherwise inherit from the 'primer' theme.
-# This is a problem because, Jekyll/Sass/Primer fails to compile by default, yay.
-# - https://github.com/jekyll/jekyll/issues/7426
-# - https://github.com/jekyll/jekyll/issues/4268
-# - https://github.com/sindresorhus/gulp-ruby-sass/issues/232
-# – Workaround: https://github.com/github/pages-gem/issues/613
-theme: null
 # Files that will not be converted or published
 exclude:
   # Exclude repo docs from site output and search index
@@ -45,6 +36,7 @@ exclude:
 # Amethyst theme options are documented at:
 # https://github.com/qunitjs/jekyll-theme-amethyst/blob/main/docs/config.md
 #
+theme: jekyll-theme-amethyst
 amethyst:
   edituri_base: https://github.com/qunitjs/jekyll-theme-amethyst/blob/main/
   release_base: https://github.com/qunitjs/qunit/releases/tag/

amethyst.gemspec

@@ -0,0 +1,23 @@
+Gem::Specification.new do |spec|
+  spec.name     = "jekyll-theme-amethyst"
+  spec.version  = "0.1.1"
+  spec.summary  = "https://github.com/qunitjs/jekyll-theme-amethyst"
+  spec.authors  = ["Timo Tijhof", "Trent Willis"]
+  spec.files    = `git ls-files -z`.split("\x0")
+
+  spec.license   = "MIT"
+  spec.homepage  = "https://github.com/qunitjs/jekyll-theme-amethyst"
+
+  spec.metadata["plugin_type"] = "theme"
+  spec.require_paths = ["lib"]
+
+  spec.add_runtime_dependency "jekyll", ">= 4.2", "< 5.0"
+  spec.add_runtime_dependency "kramdown-parser-gfm", "~> 1.1.0"
+  spec.add_runtime_dependency "jekyll-redirect-from", "~> 0.16.0"
+  spec.add_runtime_dependency "jekyll-relative-links", "~> 0.6.1"
+  # For blog
+  spec.add_runtime_dependency "jekyll-feed", "~> 0.15.1"
+  spec.add_runtime_dependency "jekyll-archives", "~> 2.2.1"
+  # Temporary fix until there is a release with https://github.com/jekyll/jekyll/pull/8524/
+  spec.add_runtime_dependency "webrick", "~> 1.7"
+end