update README

README.md

@@ -1,4 +1,7 @@
-[![Build Status](https://travis-ci.org/alastairruhm/ipsearch.svg?branch=master)](https://travis-ci.org/alastairruhm/ipsearch) [![Coverage Status](https://coveralls.io/repos/github/alastairruhm/ipsearch/badge.svg?branch=master)](https://coveralls.io/github/alastairruhm/ipsearch?branch=master) [![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![GitHub release](https://img.shields.io/github/release/alastairruhm/ipsearch.svg)](https://github.com/alastairruhm/ipsearch/releases)
+[![Build Status](https://travis-ci.org/alastairruhm/ipsearch.svg?branch=master)](https://travis-ci.org/alastairruhm/ipsearch) 
+[![Coverage Status](https://coveralls.io/repos/github/alastairruhm/ipsearch/badge.svg?branch=master)](https://coveralls.io/github/alastairruhm/ipsearch?branch=master) 
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
 
 # ipsearch
 
@@ -12,24 +15,30 @@ Use [`go get`](https://golang.org/cmd/go/#hdr-Download_and_install_packages_and_
 $ go get -u github.com/alastairruhm/ipsearch
 ```
 
+Or without golang installed, you can download binary from [release page](https://github.com/alastairruhm/ipsearch/releases), rename it with `ipsearch` and place it in $PATH directory.
+
 ## Usage
 
 From the commandline, `ipsearch` provides the functions as follows.By default, it prints its output to `stdout`.
 
 example: 
 
 ```sh
-
 # IP
 $ ipsearch 8.8.8.8
 8.8.8.8 GOOGLE-GOOGLE-google.com
 
-# host
-$ ipsearch github.com
-ipsearch github.com
-lookup host: github.com
-192.30.253.112 美国-弗吉尼亚州-阿什本
-192.30.253.113 美国-弗吉尼亚州-阿什本
+# domain
+$ ipsearch github.io
+lookup host: github.io
+23.235.37.133 FASTLY-FASTLY-fastly.com
+23.235.33.133 FASTLY-FASTLY-fastly.com
+
+# sub-domain
+$ ipsearch api.github.com
+lookup host: api.github.com
+192.30.253.117 美国-弗吉尼亚州-阿什本
+192.30.253.116 美国-弗吉尼亚州-阿什本
 
 # URL
 $ ipsearch https://github.com/alastairruhm/ipsearch