Added GitHub Actions workflow

guestbook-go/.github/workflows/main.yml

@@ -0,0 +1,57 @@
+name: Publish Docker Image
+
+on:
+    push:
+        branches: ['master']
+
+jobs:
+    build:
+        name: Push Docker Image to Docker Hub
+        runs-on: Ubuntu-latest
+
+        steps:
+            - name: Checkout Repository
+              uses: actions/checkout@v2
+          
+            - name: Setup Docker Buildx
+              uses: docker/setup-buildx-action@v1
+          
+            - name: Cache Docker Layers
+              uses: actions/cache@v2
+              with:
+                path: /tmp/.buildx-cache
+                key: ${{ runner.os }}-buildx-${{ github.sha }}
+                restore-keys: |
+                  ${{ runner.os }} -buildx-
+          
+            - name: Run Tests
+              run: |
+                # Add comments to run your tests here
+                echo "Running tests..."
+                # Example: go test ./...
+                go test ./...
+          
+            - name: Login to Docker Hub
+              uses: docker/login-action@v1
+              with:
+                username: ${{ secrets.DOCKER_USERNAME }}
+                password: ${{ secrets.DOCKER_PASSWORD }}
+          
+            - name: Build and Push Docker Image
+              uses: docker/build-push-action@v2
+              with:
+                context: .
+                file: ./Dockerfile
+                push: true
+                tags: |
+                  ${{ secrets.DOCKER_USERNAME }}/guestbook-go:latest
+                  ${{ secrets.DOCKER_USERNAME }}/guestbook-go:${{ github.sha }}
+                cache-from: type=local, src=/tmp/.buildx-cache
+                cache-to: type=local, dest=/tmp/.buildx-cache-new
+          
+            - name: Post Build Cleanup
+              run: rm -rf /tmp/.buildx-cache-new
+          
+
+
+