add workflow to build and publish docker image

Author: ghandmann

.github/workflows/docker-image.yml

@@ -0,0 +1,23 @@
+name: Build and Publish Docker Image
+
+on:
+  push:
+    tags:
+      - '*'
+jobs:
+  push_to_registry:
+    name: Push Docker image to Docker Hub
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@v2
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_PASSWORD }}
+      - name: Push to Docker Hub
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: ghandmann/contacts-api:latest