add action

.github/workflows/build_docker.yaml

@@ -0,0 +1,35 @@
+name: Build Docker Image
+
+on:
+  release: 
+    types: [published, edited]
+
+jobs:
+
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+
+      - name: Get Version from Git Tag
+        id: version
+        run: | 
+          echo "VERSION=$(git describe --tags --abbrev=0)" >> $GITHUB_ENV
+          echo "VERSION=$(git describe --tags --abbrev=0)" >> $GITHUB_OUTPUT
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v6
+        with:
+          file: Dockerfile
+          context: .
+          push: true
+          tags: "lutraconsulting/mergin-db-sync:${{steps.version.outputs.VERSION}},lutraconsulting/mergin-db-sync:latest"
+