Update README.md (#50)

Author: amogkam

README.md

@@ -86,6 +86,9 @@ You no longer have to set environment variables or configurations and run your t
 Example using `ray_lightning` with Tune:
 
 ```python
+from ray_lightning import RayPlugin
+from ray_lightning.tune import TuneReportCallback
+
 def train_mnist(config):
 
     # Create your PTL model.