Add publish CI

.github/workflows/publish.yml

@@ -0,0 +1,37 @@
+---
+name: Publish
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish:
+    if: github.event_name == 'release'
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Parse the git tag
+        id: get_tag
+        run: echo ::set-output name=TAG::$(echo $GITHUB_REF | cut -d / -f 3)
+      - name: Docker meta
+        id: docker_meta
+        uses: crazy-max/ghaction-docker-meta@v1
+        with:
+          # list of Docker images to use as base name for tags
+          images: |
+            djjudas21/ecowitt-exporter
+
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          push: true
+          tags: ${{ steps.docker_meta.outputs.tags }}
+      - name: Image digest
+        run: echo ${{ steps.docker_build.outputs.digest }}