Automate publish of docker images (#104)

.github/workflows/docker-build-push.yml

@@ -0,0 +1,31 @@
+name: Publish Docker image
+
+on:
+  push:
+    tags:
+      - '*'
+
+jobs:
+  publish-docker:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Set up Go 1.14
+        uses: actions/[email protected]
+        with:
+          go-version: 1.14
+      - name: Check out code
+        uses: actions/checkout@v2
+      - name: Build
+        run: make unit-tests
+
+      - name: Build and push Docker images on new git tags
+        uses: docker/build-push-action@v1
+        with:
+          username: ${{ secrets.DOCKER_HUB_USERNAME }}
+          password: ${{ secrets.DOCKER_HUB_PASSWORD }}
+          repository: expediagroup/mittens
+          tag_with_ref: true
+          tags: latest
+          push: ${{ startsWith(github.ref, 'refs/tags/') }}