add dockerfiles, setup workflows

.github/workflows/docker-push.yml

@@ -0,0 +1,58 @@
+name: publish
+
+on: push
+
+jobs:
+  build-and-push-images:
+    strategy:
+      matrix:
+        app:
+          - name: backend
+            file: backend.Dockerfile
+          - name: webapp
+            file: webapp.Dockerfile
+          - name: maintenance
+            file: maintenance.Dockerfile
+    runs-on: ubuntu-latest
+    env:
+      REGISTRY: ghcr.io
+      IMAGE_NAME: ${{ github.repository }}/${{ matrix.app.name }}
+    permissions:
+      contents: read
+      packages: write
+      attestations: write
+      id-token: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.1.7
+      - name: Log in to the Container registry
+        uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@70b2cdc6480c1a8b86edf1777157f8f437de2166
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=schedule
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=semver,pattern={{major}}
+            type=ref,event=branch
+            type=ref,event=pr
+            type=sha
+      - name: Build and push Docker images
+        id: push
+        uses: docker/build-push-action@4f58ea79222b3b9dc2c8bbdd6debcef730109a75
+        with:
+          file:  ${{ matrix.app.file }}
+          push: true
+          build-args:
+            APP_IMAGE_TAG_CODE: ${{ github.head_ref || github.ref_name }}-code
+            APP_IMAGE_TAG_BASE: ${{ github.head_ref || github.ref_name }}-base
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}