[docs] add Kubeflow operator repo and link to example (#3632)

* Update README.md

* Update Parallel-Learning-Guide.rst

* Update Parallel-Learning-Guide.rst

README.md

@@ -80,6 +80,8 @@ MMLSpark (LightGBM on Spark): https://github.com/Azure/mmlspark
 
 Kubeflow Fairing (LightGBM on Kubernetes): https://github.com/kubeflow/fairing
 
+Kubeflow Operator (LightGBM on Kubernetes): https://github.com/kubeflow/xgboost-operator
+
 ML.NET (.NET/C#-package): https://github.com/dotnet/machinelearning
 
 LightGBM.NET (.NET/C#-package): https://github.com/rca22/LightGBM.Net

docs/Parallel-Learning-Guide.rst

@@ -14,6 +14,8 @@ Follow the `Quick Start <./Quick-Start.rst>`__ to know how to use LightGBM first
 
 -  `Kubeflow Fairing`_ suggests using LightGBM in a Kubernetes cluster.
    `These examples`_ help to get started with LightGBM in a hybrid cloud environment.
+   Also you can use `Kubeflow XGBoost Operator`_ to train LightGBM model.
+   Please check `this example`_ for how to do this.
 
 Choose Appropriate Parallel Algorithm
 -------------------------------------
@@ -142,6 +144,9 @@ Example
 
 .. _These examples: https://github.com/kubeflow/fairing/tree/master/examples/lightgbm
 
+.. _Kubeflow XGBoost Operator: https://github.com/kubeflow/xgboost-operator
+
+.. _this example: https://github.com/kubeflow/xgboost-operator/tree/master/config/samples/lightgbm-dist
 
 .. _here: https://www.youtube.com/watch?v=iqzXhp5TxUY