build a docker image and push to ghcr.io

.github/workflows/docker.yml

@@ -0,0 +1,43 @@
+name: docker
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  docker-build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        id: buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Login to Github Packages
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          images: ghcr.io/swaggo/swag
+
+      - name: Build image and push to GitHub Container Registry
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: |
+            ghcr.io/swaggo/swag:latest
+            ghcr.io/swaggo/swag:${{github.ref_name}}
+          labels: ${{ steps.meta.outputs.labels }}
+
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}