Add CI action to build and deploy Docker image

.github/workflows/docker.yml

@@ -0,0 +1,42 @@
+name: Docker Image CI
+
+env:
+  IMAGE_NAME: mirror-to-gitea
+
+on:
+  push:
+    tags:
+      - '**'
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Login to Docker Hub
+      uses: docker/login-action@v1
+      with:
+        username: ${{ secrets.DOCKERHUB_USER }}
+        password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+    - name: Set up Docker Buildx
+      uses: docker/setup-buildx-action@v2
+      with:
+        driver: docker-container
+        driver-opts: |
+          image=moby/buildkit:master
+          network=host
+
+    - name: Build and push
+      uses: docker/build-push-action@v2
+      with:
+        context: ./
+        file: ./Dockerfile
+        builder: ${{ steps.buildx.outputs.name }}
+        push: true
+        tags: ${{ secrets.DOCKERHUB_USER }}/${{ env.IMAGE_NAME }}:latest
+        cache-from: type=registry,ref=${{ secrets.DOCKERHUB_USER }}/${{ env.IMAGE_NAME }}:buildcache
+        cache-to: type=registry,ref=${{ secrets.DOCKERHUB_USER }}/${{ env.IMAGE_NAME }}:buildcache,mode=max