feat: enhance Docker workflow to support logging in and pushing images to Docker Hub; update README with new run command options

.github/workflows/monolith.yml

@@ -7,6 +7,7 @@ on:
 
 env:
   REGISTRY_URL: gitea.kobim.cloud
+  DOCKERHUB_USERNAME: kobimex
 
 jobs:
   build:
@@ -18,20 +19,37 @@ jobs:
       - name: Setup Docker Environment
         uses: ./.github/actions/setup-docker-environment
         
-      - name: Log in to Docker registry
+      - name: Log in to custom Docker registry
         uses: docker/login-action@v3.3.0
         with:
           registry: ${{ env.REGISTRY_URL }}
           username: ${{ github.actor }}
           password: ${{ secrets.REGISTRY_TOKEN }}
           
-      - name: Build and push Docker image
+      - name: Build and push Docker image to custom registry
         uses: docker/build-push-action@v6.13.0
         with:
           context: .
           push: true
           tags: ${{ env.REGISTRY_URL }}/${{ github.repository_owner }}/${{ github.event.repository.name }}-monolith:latest
           file: ./Monolith.dockerfile
+          platforms: |
+            linux/amd64
+            linux/arm64
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3.3.0
+        with:
+          username: ${{ env.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push Docker image to Docker Hub
+        uses: docker/build-push-action@v6.13.0
+        with:
+          context: .
+          push: true
+          tags: ${{ env.DOCKERHUB_USERNAME }}/${{ github.event.repository.name }}-monolith:latest
+          file: ./Monolith.dockerfile
           platforms: |
             linux/amd64
             linux/arm64