Update README.md (#1839)

A quick update for the NNI short introduction.

README.md

@@ -14,8 +14,7 @@
 
 [简体中文](README_zh_CN.md)
 
-NNI (Neural Network Intelligence) is a toolkit to help users run automated machine learning (AutoML) experiments.
-The tool dispatches and runs trial jobs generated by tuning algorithms to search the best neural architecture and/or hyper-parameters in different environments like local machine, remote servers and cloud.
+**NNI (Neural Network Intelligence)** is an efficient and automatic toolkit to help users design and search neural network architecture, tune machine learning model's parameters or complex system's parameters. The tool manages automated machine learning (AutoML) experiments, dispatches and runs experiments' trial jobs generated by tuning algorithms to search the best neural architecture and/or hyper-parameters in different environments like local machine, remote servers and cloud.
 
 
 ### **NNI v1.2 has been released! &nbsp;<a href="#nni-released-reminder"><img width="48" src="docs/img/release_icon.png"></a>**