Added GitHub Actions workflow to publish Docker image to GitHub Container Registry

.github/workflows/publish-image.yaml

@@ -0,0 +1,14 @@
+name: Docker image CI for GHCR
+
+on: push
+
+jobs:
+  build_and_publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Build and push image
+        run: |
+          docker login --username anaxios --password ${{ secrets.GH_TOKEN }} ghcr.io
+          docker build . --tag ghcr.io/anaxios/holesail-docker:latest
+          docker push ghcr.io/anaxios/holesail-docker:latest