Update README; fix workflow file

Author: Jskobos

.github/workflows/publish.yaml

@@ -7,11 +7,11 @@ jobs:
     name: Docker Build and Push
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v1
       - uses: docker/build-push-action@v1
         with:
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
-          dockerfile: .
           repository: jskobos/elm-terminal-resume
           tag_with_ref: true
           push: ${{ startsWith(github.ref, 'refs/tags/') }}