update README

README.md

@@ -5,4 +5,42 @@
 
 goClustering is an implementation of following clustering algorithm in Golang.
 
-## Ward's method
+## Ward's method
+
+Ward's method is a distance criterion in hierarchical cluster algorithm.
+This method put two groups into one to minimize the total within-cluster variance. For detail, see [here](https://en.wikipedia.org/wiki/Ward%27s_method).
+
+## How to Install
+
+You can get goClustering by using go get:
+
+```sh
+go get github.com/cipepser/goClustering/...
+```
+
+## Example
+
+```go
+package main
+
+import (
+	"fmt"
+
+	"github.com/cipepser/goClustering/ward"
+)
+
+func main() {
+	X := [][]float64{
+		{0, 0},
+		{1, 0},
+		{5, 0},
+	}
+
+	T := ward.Ward(X)
+
+	fmt.Println(T)
+}
+```
+
+## References
+* [Ward's method](https://en.wikipedia.org/wiki/Ward%27s_method)