Add readme documentation

README.md

-# Permission handler
+# Flutter Permission handler Plugin
 
 
-Permission plugin for Flutter. This plugin provides a cross-platform (iOS, Android) API to request and check permissions.
+[![pub package](https://img.shields.io/pub/v/permission_handler.svg)](https://pub.dartlang.org/packages/permission_handler)
+
+A permissions plugin for Flutter. This plugin provides a cross-platform (iOS, Android) API to request and check permissions.
+
+Branch  | Build Status 
+------- | ------------
+develop | [![Build Status](https://travis-ci.com/BaseflowIT/flutter-permission-handler.svg?branch=develop)](https://travis-ci.com/BaseflowIT/flutter-permission-handler)
+master  | [![Build Status](https://travis-ci.com/BaseflowIT/flutter-permission-handler.svg?branch=master)](https://travis-ci.com/BaseflowIT/flutter-permission-handler)
+
+## Features
+
+* Check if a permission is granted.
+* Request permission for a specific feature.
+
+## Usage
+
+To use this plugin, add `permission-handler` as a [dependency in your pubspec.yaml file](https://flutter.io/platform-plugins/). For example:
+
+```yaml
+dependencies:
+  permission-handler: '^1.0.0'
+```
+
+> **NOTE:** There's a known issue with integrating plugins that use Swift into a Flutter project created with the Objective-C template. See issue [Flutter#16049](https://github.com/flutter/flutter/issues/16049) for help on integration.
+
+## API
+
+### Requesting permission
+
+``` dart
+import 'package:permission_handler/permission_handler.dart';
+
+Map<PermissionGroup, PermissionStatus> permissions = await PermissionHandler().requestPermissions(PermissionGroup.Contacts);
+```
+
+### Checking permission
+
+``` dart
+import 'package:permission_handler/permission_handler.dart';
+
+PermissionStatus permission = await PermissionHandler().checkPermissionStatus(PermissionGroup.Contacts);
+```
+
+### Open app settings
+
+``` dart
+import 'package:permission_handler/permission_handler.dart';
+
+bool isOpened = await PermissionHandler().openAppSettings();
+```
+
+### Show a rationale for requesting permission
+
+``` dart
+import 'package:permission_handler/permission_handler.dart';
+
+bool isShown = await PermissionHandler().shouldShowRequestPermissionRationale(PermissionGroup.Contacts);
+```
+
+### List of available permissions
+
+Defines the permission groups for which permissions can be checked or requested.
+
+``` dart
+enum PermissionGroup {
+  /// The unknown permission only used for return type, never requested
+  unknown,
+
+  /// Android: Calendar
+  /// iOS: Calendar (Events)
+  calendar,
+
+  /// Android: Camera
+  /// iOS: Photos (Camera Roll and Camera)
+  camera,
+
+  /// Android: Contacts
+  /// iOS: AddressBook
+  contacts,
+
+  /// Android: Fine and Coarse Location
+  /// iOS: CoreLocation (Always and WhenInUse)
+  location,
+
+  /// Android: Microphone
+  /// iOS: Microphone
+  microphone,
+
+  /// Android: Phone
+  /// iOS: Nothing
+  phone,
+
+  /// Android: Nothing
+  /// iOS: Photos
+  photos,
+
+  /// Android: Nothing
+  /// iOS: Reminders
+  reminders,
+
+  /// Android: Body Sensors
+  /// iOS: CoreMotion
+  sensors,
+
+  /// Android: Sms
+  /// iOS: Nothing
+  sms,
+
+  /// Android: External Storage
+  /// iOS: Nothing
+  storage,
+
+  /// Android: Microphone
+  /// iOS: Speech
+  speech,
+
+  /// Android: Fine and Coarse Location
+  /// iOS: CoreLocation - Always
+  locationAlways,
+
+  /// Android: Fine and Coarse Location
+  /// iOS: CoreLocation - WhenInUse
+  locationWhenInUse,
+
+  /// Android: None
+  /// iOS: MPMediaLibrary
+  mediaLibrary
+}
+```
+
+### Status of the permission
+
+Defines the state of a permission group
+
+``` dart
+enum PermissionStatus {
+  /// Permission to access the requested feature is denied by the user.
+  denied,
+
+  /// The feature is disabled (or not available) on the device.
+  disabled,
+
+  /// Permission to access the requested feature is granted by the user.
+  granted,
+
+  /// The user granted restricted access to the requested feature (only on iOS).
+  restricted,
+
+  /// Permission is in an unknown state
+  unknown
+}
+```
+
+## Issues
+
+Please file any issues, bugs or feature request as an issue on our [GitHub](https://github.com/BaseflowIT/flutter-permission-handler/issues) page.
 
 
 ## Want to contribute
 ## Want to contribute
 
 
@@ -8,4 +163,4 @@ If you would like to contribute to the plugin (e.g. by improving the documentati
 
 
 ## Author
 ## Author
 
 
-The Permission handler plugin for Flutter is developed by [Baseflow](https://baseflow.com). You can contact us at <hello@baseflow.com>.
+This Permission handler plugin for Flutter is developed by [Baseflow](https://baseflow.com). You can contact us at <hello@baseflow.com>