update README

Author: johnfercher

README.md

@@ -58,6 +58,7 @@ package main
 
 import (
 	"fmt"
+	"github.com/johnfercher/go-tree/node"
 
 	"github.com/johnfercher/go-tree/tree"
 )
@@ -66,24 +67,24 @@ import (
 func main() {
 	tr := tree.New[string]()
 
-	tr.AddRoot(tree.NewNode(0, "0.0"))
+	tr.AddRoot(node.New("0.0").WithID(0))
 
-	tr.Add(0, tree.NewNode(1, "0.1"))
-	tr.Add(0, tree.NewNode(2, "0.2"))
+	tr.Add(0, node.New("0.1").WithID(1))
+	tr.Add(0, node.New("0.2").WithID(2))
 
-	tr.Add(1, tree.NewNode(3, "1.3"))
-	tr.Add(1, tree.NewNode(4, "1.4"))
+	tr.Add(1, node.New("1.3").WithID(3))
+	tr.Add(1, node.New("1.4").WithID(4))
 
-	tr.Add(2, tree.NewNode(5, "2.5"))
-	tr.Add(2, tree.NewNode(6, "2.6"))
+	tr.Add(2, node.New("2.5").WithID(5))
+	tr.Add(2, node.New("2.6").WithID(6))
 
 	root, ok := tr.GetRoot()
-	fmt.Println(ok)         // true
-	fmt.Println(root.Get()) // 0, 0.0
+	fmt.Println(ok)             // true
+	fmt.Println(root.GetData()) // 0.0
 
 	node, ok := tr.Get(3)
-	fmt.Println(ok)         // true
-	fmt.Println(node.Get()) // 3, 1.3
+	fmt.Println(ok)             // true
+	fmt.Println(node.GetData()) // 1.3
 
 	structure, ok := tr.GetStructure()
 	fmt.Println(ok)        // true
@@ -92,7 +93,7 @@ func main() {
 	nodes, ok := tr.Backtrack(6)
 	fmt.Println(ok) // true
 	for _, node := range nodes {
-		fmt.Println(node.Get()) // 6, 2.6; 2, 0.2; 0, 0.0
+		fmt.Println(node.GetData()) // 2.6; 0.2; 0.0
 	}
 }
 ```