feat(ci/cd): build and push docker image

.github/workflows/docker-build.yml

@@ -0,0 +1,28 @@
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to DockerHub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Build and push Docker image
+        run: |
+          docker build -t pihkaal/simple-qr:latest .
+          docker push pihkaal/simple-qr:latest