Add workflow for automatically building and pushing image to Dockerhub

.github/workflows/release.yaml

@@ -0,0 +1,30 @@
+name: Publish Release
+on:
+  push:
+    branches: [ master ]
+  release:
+    types: [ published ]
+jobs:
+  release:
+    name: Docker Hub Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+      - name: Login to Docker Hub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: caseyscarborough/qbittorrent-exporter
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}