[dotbox] Add GitHub Actions

.github/workflows/dotbox.yml

@@ -0,0 +1,25 @@
+name: dotbox
+
+on:
+  release:
+    types: [created]
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Build the Docker image
+        run: docker build -t dotbox dotbox
+
+      - name: Get release version
+        run: echo ::set-env name=RELEASE_VERSION::${GITHUB_REF:10}
+
+      - name: Publish to the Docker Hub
+        run: |
+            docker login --username "${{ github.actor }}" --password "${{ secrets.DOCKER_HUB_TOKEN }}"
+            docker tag dotbox "${{ github.actor }}/dotbox:${{ env.RELEASE_VERSION }}"
+            docker push "${{ github.actor }}/dotbox:${{ env.RELEASE_VERSION }}"