add: build and publish docker image job

.github/workflows/publish.yaml

@@ -0,0 +1,55 @@
+name: Create and publish a Docker image
+
+on:
+  push:
+    branches:
+      - main
+
+env:
+  REGISTRY: ghcr.io
+
+jobs:
+  build-and-push-image:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - path: ./backend
+            image: ghcr.io/${{ github.repository }}/backend
+          - path: ./frontend
+            image: ghcr.io/${{ github.repository }}/frontend
+    permissions:
+      contents: read
+      packages: write
+      attestations: write
+      id-token: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Log in to the Container registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ matrix.image }}
+      - name: Build and push Docker image
+        id: push
+        uses: docker/build-push-action@v6
+        with:
+          context: ${{ matrix.path }}
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+      - name: Generate artifact attestation
+        uses: actions/attest-build-provenance@v1
+        with:
+          subject-name: ${{ env.REGISTRY }}/${{ matrix.image }}
+          subject-digest: ${{ steps.push.outputs.digest }}
+          push-to-registry: true
+