adding Dockerfile build step.

.github/workflows/ci.yaml

@@ -1,12 +1,18 @@
 name: CI
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
 # This workflow is triggered on pushes & pull requests
 on:
   pull_request:
     branches:
       - main
   push:
     branches: [ main ]
+  release:
+    types: [published]
 jobs:
+
   test:
     name: Test
     runs-on: ubuntu-latest
@@ -36,3 +42,49 @@ jobs:
           flags: unittests
           fail_ci_if_error: true
           verbose: true
+  docker:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+      id-token: write
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+      - name: Log into registry ${{ env.REGISTRY }}
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v2
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      # Extract metadata (tags, labels) for Docker
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          flavor: |
+            # only latest if push has a tag and we're building the "main" flavor
+            latest=${{ github.event_name == 'release' && github.ref_type == 'tag' }}
+          tags: |
+            # if this is a tag'd build, prefix it with the flavor (eg. main-v1.2.3 and sandbox-v1.2.3)
+            type=ref,event=tag
+            # if this is a main branch build, just tag it with the flavor (eg. main and sandbox)
+            type=raw,value=${{ github.ref_name }},enable=${{  github.ref_name == 'main' }}
+            # if this is a (non main) branch build, tag it with the flavor and branch name (eg. main-branch and sandbox-branch)
+            type=ref,event=branch,enable=${{ github.ref_name != 'main' }}
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+      # 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:
+          platforms: linux/amd64,linux/arm64
+          context: .
+          file: Dockerfile
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}