修改了example

给readme增加了一个简单的内测攻略

README.md

 # photo
 
-A new flutter package project.
+## 内测中
 
-## Getting Started
+install
+```yaml
+dependencies:
 
-For help getting started with Flutter, view our online [documentation](https://flutter.io/).
+  photo:
+    git: https://github.com/CaiJingLong/flutter_photo
+    ref: 5affef481c63a314333b40b4f26e1dc689c15c00 # 这里的ref看情况修改也可
+```
 
-For help on editing package code, view the [documentation](https://flutter.io/developing-packages/).
+import
+```dart
+import 'package:photo/photo.dart';
+import 'package:photo_manager/photo_manager.dart';
+```
+
+调用
+```dart
+void _pickImage() async{
+    List<ImageEntity> imgList = await PhotoPicker.pickImage(
+      context: context,
+      themeColor: Colors.green,
+      padding: 5.0,
+      dividerColor: Colors.deepOrange,
+      disableColor: Colors.grey.shade300,
+      itemRadio: 0.88,
+    );
+
+    print(imgList);
+  }
+
+```

example/lib/main.dart

 import 'package:flutter/material.dart';
 import 'package:photo/photo.dart';
+import 'package:photo_manager/photo_manager.dart';
 
 void main() => runApp(new MyApp());
 
 class _MyHomePageState extends State<MyHomePage> {
 
   void _pickImage() async{
-    var imgList = await PhotoPicker.pickImage(
+    List<ImageEntity> imgList = await PhotoPicker.pickImage(
       context: context,
       themeColor: Colors.green,
       padding: 5.0,

lib/photo.dart

 import 'package:photo/src/ui/photo_app.dart';
 import 'package:photo_manager/photo_manager.dart';
 
-/// A Calculator.
 class PhotoPicker {
   static PhotoPicker _instance;
 
     return _instance;
   }
 
+  
+
   /// 没有授予权限的时候,会开启一个dialog去帮助用户去应用设置页面开启权限
   /// 确定开启设置页面,取消关闭弹窗
   ///