Github: Add deploy action

.github/workflows/deploy.yml

@@ -0,0 +1,34 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v3
+
+    - name: Install nix
+      uses: cachix/install-nix-action@v24
+      with:
+        github_access_token: ${{ secrets.GITHUB_TOKEN }}
+
+    - name: Build website
+      run: |
+        nix develop .#deploy
+        trunk serve --release
+
+    - name: Fix links
+      run: sh fix-links.sh
+
+    - name: Deploy to GitHub pages
+      uses: JamesIves/github-pages-deploy-action@v4
+      with:
+        branch: pages  # The branch the action should deploy to.
+        folder: dist   # The folder the action should deploy.
+        clean: true    # Automatically remove deleted files from the deployment branch.