add initial GitHub action for building and pushing Docker images

Signed-off-by: Peter Stadler <[email protected]>

.github/workflows/docker-publish.yml

@@ -0,0 +1,65 @@
+name: Docker
+
+on:
+  # run on every push to any branch
+  push:
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      # Login against a Docker registry except on PR
+      # https://github.com/docker/login-action
+      - name: Log in to GitHub registry
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: TEITechnicalCouncil
+          password: ${{ secrets.TEITECHNICALCOUNCIL_PACKAGES_TOKEN }}
+
+      # Login against DockerHub registry except on PR
+      - name: Log in to DockerHub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.PETERS_DOCKERHUB_USERNAME }}
+          password: ${{ secrets.PETERS_DOCKERHUB_TOKEN }}
+
+      # Extract metadata (tags, labels) for Docker
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: |
+            ghcr.io/teic/romajs
+            teic/romajs
+          flavor: |
+            latest=${{ github.ref == 'refs/heads/main' }}
+
+      # Build and push Docker image with Buildx (don't push on PR)
+      # https://github.com/docker/build-push-action
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: ${{ github.event_name != 'pull_request' }}
+          platforms: |
+            linux/amd64
+            linux/arm64/v8
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}