Add docker support

.github/workflows/push_image.yml

@@ -0,0 +1,31 @@
+name: Docker Image CI
+
+on:
+  push:
+    branches: ["main"]
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v2
+
+        with:
+          registry: registry.cn-shanghai.aliyuncs.com
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          push: true
+          tags: usual2970/certimate:latest