Setup GitHub Action

.github/workflows/main.yml

@@ -0,0 +1,15 @@
+name: build-and-deploy
+on: push
+jobs:
+  deploy:
+    runs-on: ubuntu-18.04
+    steps:
+      - name: Git checkout
+        uses: actions/checkout@v2
+      - name: Build
+        run: make build
+      - name: Deploy
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          deploy_key: ${{ secrets.ACTIONS_DEPLOY_KEY }}
+          publish_dir: ./_book