Revive the site for the hosted app

.github/dependabot.yml

@@ -0,0 +1,16 @@
+version: 2
+updates:
+  - package-ecosystem: bundler
+    directory: /
+    schedule:
+      interval: weekly
+    groups:
+      bundler:
+        patterns: ["*"]
+  - package-ecosystem: github-actions
+    directory: /
+    schedule:
+      interval: weekly
+    groups:
+      github-actions:
+        patterns: ["*"]

.github/workflows/pages.yml

@@ -0,0 +1,50 @@
+name: Pages
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: pages-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: ruby/setup-ruby@v1
+        with:
+          bundler-cache: true
+      - id: pages
+        uses: actions/configure-pages@v5
+        if: github.event_name != 'pull_request'
+      - name: Build
+        run: bundle exec jekyll build
+        env:
+          JEKYLL_ENV: production
+      - name: Check links
+        run: make test
+        env:
+          LANG: C.UTF-8
+      - uses: actions/upload-pages-artifact@v4
+        if: github.event_name != 'pull_request'
+
+  deploy:
+    if: github.event_name != 'pull_request' && github.ref == 'refs/heads/master'
+    needs: build
+    runs-on: ubuntu-latest
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - id: deployment
+        uses: actions/deploy-pages@v4

.ruby-version

@@ -0,0 +1 @@
+3.3.6

Gemfile

@@ -1,6 +1,12 @@
 source "https://rubygems.org"
 
-gem "github-pages"
-gem "jekyll-seo-tag"
-gem "rouge"
-gem "html-proofer"
+gem "jekyll", "~> 4.4"
+
+group :jekyll_plugins do
+  gem "jekyll-seo-tag", "~> 2.8"
+  gem "jekyll-sitemap", "~> 1.4"
+end
+
+group :test do
+  gem "html-proofer", "~> 5.0"
+end