Update README

README.md

@@ -1 +1,25 @@
-# goxirr
+# goxirr
+[![GoDoc](https://godoc.org/github.com/maksim77/goxirr?status.svg)](https://godoc.org/github.com/maksim77/goxirr)
+
+Goxirr is a simple implementation of a function for calculating the Internal Rate of Return for irregular cash flow (XIRR).
+
+## Example
+
+```go
+import "time"
+
+import "github.com/maksim77/goxirr"
+
+firstDate := time.Date(2019, time.January, 1, 0, 0, 0, 0, time.UTC)
+t1 := goxirr.Transaction{
+	Date: firstDate,
+	Cash: -100,
+}
+t2 := goxirr.Transaction{
+    Date: firstDate.Add(time.Hour * 24 * 365),
+    Cash: 112,
+}
+
+tas := goxirr.Transactions{t1, t2}
+fmt.Println(goxirr.Xirr(tas))
+```