Added a github workflow to automatically build and publish the latest from the main branch to docker hub.

.github/workflows/docker_build_workflow.yml

@@ -0,0 +1,40 @@
+name: Build and Push Docker Image
+
+on:
+  workflow_run:
+    workflows: ["Run Ubuntu Headless ebook2audiobook"]
+    types:
+      - completed
+  release:
+    types:
+      - published  # Trigger on release creation
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.workflow_run.conclusion == 'success' && github.event_name == 'release' }}  # Trigger if workflow passed and release published
+
+    steps:
+      # Checkout the repository code
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      # Log in to Docker Hub or GitHub Container Registry
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      # Build the Docker image with multiple tags
+      - name: Build Docker image
+        run: |
+          GIT_HASH=$(git rev-parse --short=9 HEAD)
+          docker build -t ${{ secrets.DOCKER_USERNAME }}/ebook2audiobook:latest_small -t ${{ secrets.DOCKER_USERNAME }}/ebook2audiobook:$GIT_HASH .
+
+      # Push the Docker image to the registry
+      - name: Push Docker image
+        run: |
+          GIT_HASH=$(git rev-parse --short=9 HEAD)
+          docker push ${{ secrets.DOCKER_USERNAME }}/ebook2audiobook:latest_small
+          docker push ${{ secrets.DOCKER_USERNAME }}/ebook2audiobook:$GIT_HASH