feat: add GitHub workflow to build and push to Docker Hub

This adds a new docker-hub.yaml workflow that builds and pushes any
commit to main into Docker Hub directly.

And uses that built image in the compose file.

.github/workflows/docker-hub.yaml

@@ -0,0 +1,40 @@
+name: Docker Hub
+
+# Currently, we publish every commit to main into Docker hub.
+# In the future, we may to trigger off of actual releases.
+on:
+  pull_request:
+#  push:
+#    branches:
+#      - main
+
+jobs:
+  push_to_docker_hub:
+    name: Build and push image
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Get Docker metadata
+        id: meta
+        uses: docker/metadata-action@v4
+        with:
+          flavor: latest=true
+          images: smartonfhir/cumulus-etl
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v2
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+
+      - name: Build and push image to Docker Hub
+        uses: docker/build-push-action@v4
+        with:
+          push: true
+          platforms: |
+            linux/amd64
+            linux/arm64
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}

compose.yaml

@@ -1,9 +1,7 @@
 services:
 
   cumulus-etl-base:
-    build: 
-      context: .
-      target: cumulus-etl
+    image: smartonfhir/cumulus-etl:latest
     environment:
       - AWS_ACCESS_KEY_ID
       - AWS_SECRET_ACCESS_KEY