Merge pull request #3 from jhuapl-bio/staging

Create pre-release yaml file for dockerhub push

.github/workflows/main.yml

@@ -0,0 +1,24 @@
+name: Build and push Docker image for pre-release
+
+on:
+  push:
+    branches: prerelease
+
+jobs:
+  push_to_registry:
+    name: Build and push Docker image for pre-release
+    runs-on: ubuntu-latest
+    steps:
+
+      - name: Check out the repo
+        uses: actions/checkout@v2
+
+      - name: Push to Docker Hub
+        uses: docker/build-push-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_PASSWORD }}
+          repository: ${{ secrets.DOCKERHUB_REPOSITORY }}
+          tag_with_ref: true
+          tag_with_sha: true
+          tags: prerelease