Create push-to-docker.yml

.github/workflows/push-to-docker.yml

@@ -0,0 +1,27 @@
+name: Push Heimdall Lite to Docker Hub on every merge to master and tag as latest
+
+on:
+  push:
+    branches: [ master ]
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v1
+      - name: Login to DockerHub
+        uses: docker/login-action@v1
+        with:
+          username: ${{ secrets.DOCKERHUB_USERNAME }}
+          password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: Checkout the Heimdall Repository
+        uses: actions/checkout@v2 
+      - name: Build and push
+        id: docker_build
+        uses: docker/build-push-action@v2
+        with:
+          context: .
+          file: Dockerfile.lite
+          push: true
+          tags: mitre/heimdall-lite:latest