Update readme.md

Author: kevwan

readme.md

@@ -2,6 +2,12 @@
 
 HTTP to gRPC gateway standalone. An example of go-zero gateway.
 
+## Install
+
+```shell
+go install github.com/kevwan/gateway@latest
+```
+
 ## Usage
 
 Example config:
@@ -41,4 +47,4 @@ gateway -f config.yaml
 
 ## Give a Star! ⭐
 
-If you like or are using this project, please give it a **star**. Thanks!
+If you like or are using this project, please give it a **star**. Thanks!