add CD

.github/workflows/docker.yml

@@ -0,0 +1,45 @@
+name: Docker Image CI
+
+on:
+  push:
+    branches: [ "master" ]
+  workflow_dispatch: # run manually
+
+jobs:
+
+  deploy:
+
+    runs-on: ubuntu-latest
+    permissions:
+      packages: write
+      contents: read
+   steps:
+    - name: Checkout
+      uses: actions/checkout@v4
+      with:
+        # we need tags for docker version tagging
+        fetch-tags: true
+        fetch-depth: 0
+    - # Activate cache export feature to reduce build time of images
+      name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v3
+    - name: Login to GitHub Container Registry
+      uses: docker/login-action@v3
+      with:
+        registry: ghcr.io
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+    - name: Log in to Docker Hub
+      uses: docker/login-action@v3
+      with:
+        username: ${{ secrets.DOCKERIO_USERNAME }}
+        password: ${{ secrets.DOCKERIO_PASSWORD }}
+    - name: Build the Docker image
+      # build both tags at the same time
+      run: make docker DOCKER_TAG="docker.io/ocrd/kraken -t ghcr.io/ocr-d/kraken"
+    - name: Test the Docker image
+      run: docker run --rm ocrd/kraken ocrd-kraken-segment -h
+    - name: Push to Dockerhub
+      run: docker push docker.io/ocrd/kraken
+    - name: Push to Github Container Registry
+      run: docker push ghcr.io/ocr-d/kraken