Update Readme and tidy go.mod, go.sum (#4)

* chore(readme): add godoc and fix badges

* chore(go.mod): tidy go.mod

* chore(readme): update readme

* chore(readme): update readme

README.md

@@ -1,23 +1,26 @@
 # q-radix
 
-_A cute(Q) radix tree implementation in Go/Golang with good performance._
+[![Build Status](https://travis-ci.org/ihexxa/q-radix.svg?branch=master)](https://travis-ci.org/ihexxa/q-radix)
+[![Go Report](https://goreportcard.com/badge/github.com/ihexxa/q-radix)](https://goreportcard.com/report/github.com/ihexxa/q-radix)
+[![PkgGoDev](https://pkg.go.dev/badge/github.com/ihexxa/q-radix)](https://pkg.go.dev/github.com/ihexxa/q-radix)
 
-[![](https://travis-ci.org/ihexxa/q-radix.svg?branch=master)](build)
-[![](https://goreportcard.com/badge/github.com/ihexxa/q-radix)](goreport)
+_A fast and simple (200+ lines) radix tree implementation in Go/Golang._
 
 ### Features
 
-* good performance
+* good performance ([benchmark](https://github.com/ihexxa/radix-bench))
 * more ways to query: GetAllMatches
 * simple interfaces
-* well tested (unit test and random test)
+* well tested (unit tests and random tests)
 
 ### Install
 
 Install q-radix: `go get github.com/ihexxa/q-radix`
 
 ### Examples
 
+Document is [here](https://pkg.go.dev/github.com/ihexxa/q-radix).
+
 ```go
 // import q-radix
 import qradix "github.com/ihexxa/q-radix"