Merge remote branch 'master' into github-actions

.github/workflows/ci.yml

@@ -0,0 +1,29 @@
+name: Continuous Integration
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  ruby:
+    name: "Test Backend (Jekyll ${{ matrix.jekyll_version }}, Ruby ${{ matrix.ruby_version }})"
+    runs-on: "ubuntu-latest"
+    env:
+      JEKYLL_VERSION: ${{ matrix.jekyll_version }}
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby_version: ["2.7"]
+        jekyll_version:
+          - "~> 3.9"
+          - "~> 4.0"
+    steps:
+      - name: Checkout Repository
+        uses: actions/checkout@v2
+      - name: "Set up Ruby ${{ matrix.ruby_version }}"
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby_version }}
+          bundler-cache: true