Fix example

Author: Philipp Alferov

package.json

@@ -1,6 +1,6 @@
 {
   "name": "array-to-tree",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "Convert a plain array of nodes (with pointers to parent nodes) to a tree",
   "main": "index.js",
   "scripts": {

readme.md

@@ -10,7 +10,7 @@ Solves a problem with conversion of retrieved from a database sets of data to a
 $ npm install --save array-to-tree
 ```
 
-## Usage
+## Basic Usage
 
 ```js
 var arrayToTree = require('array-to-tree');
@@ -33,7 +33,7 @@ var navigation = [{
   parent_id: null
 }];
 
-var navigationTree = arrayToTree(navigation);
+var navigationTree = arrayToTree({ data: navigation });
 
 /*
  * Output: