add build workflow

.github/workflows/generate.yml

@@ -0,0 +1,28 @@
+name: Generate
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  build:
+    if: startsWith(github.ref, 'refs/tags/')
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: denoland/setup-deno@v1
+        with:
+          deno-version: v1.x
+      - name: Run
+        run: deno task run
+      - name: Release
+        uses: fnkr/github-action-ghr@v1
+        env:
+          GHR_PATH: stations.json
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Deploy
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: stations.json