build: Initial docker build & publish workflow

.github/workflows/docker.yml

@@ -0,0 +1,18 @@
+name: Build and publish docker images to docker hub
+on: 
+  push:
+    branches:
+      - master
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: docker/build-push-action@v1
+        with:
+          path: ./docker/gms
+          username: ${{ secrets.DOCKER_USERNAME }}
+          password: ${{ secrets.DOCKER_PASSWORD }}
+          repository: linkedin/datahub-gms
+          tags: latest