Update README

• Updates our README to be consistent with our other SDK repos

Author: Nightsd01

Diff for: README.md

@@ -1,10 +1,28 @@
-# onesignal [![Build Status](https://travis-ci.org/OneSignal/OneSignal-Flutter-SDK.svg?branch=master)](https://travis-ci.org/OneSignal/OneSignal-Flutter-SDK)
+<p align="center">
+  <img src="https://onesignal.com/assets/common/logo_onesignal_color.png"/>
+</p>
 
-A new flutter plugin project.
+### OneSignal Flutter SDK [![Build Status](https://travis-ci.org/OneSignal/OneSignal-Flutter-SDK.svg?branch=master)](https://travis-ci.org/OneSignal/OneSignal-Flutter-SDK)
 
-## Getting Started
+---
 
-For help getting started with Flutter, view our online
-[documentation](https://flutter.io/).
+[OneSignal](https://onesignal.com/) is a free push notification service for mobile apps. This SDK makes it easy to integrate your Flutter iOS and/or Android apps with OneSignal.
 
-For help on editing plugin code, view the [documentation](https://flutter.io/platform-plugins/#edit-code).
+![alt text](https://onesignal.com/images/android_and_ios_notification_image.gif)
+
+#### Installation
+See the [Setup Guide](https://documentation.onesignal.com/v5.0/docs/flutter-sdk-setup) for setup instructions.
+
+#### Change Log
+See this repository's [release tags](https://github.com/onesignal/onesignal-flutter-sdk/releases) for a complete change log of every released version.
+
+#### Support
+Please visit this repository's [Github issue tracker](https://github.com/onesignal/onesignal-flutter-sdk/issues) for feature requests and bug reports related specificly to the SDK.
+For account issues and support please contact OneSignal support from the [OneSignal.com](https://onesignal.com) dashboard.
+
+#### Demo Project
+To make things easier, we have published a demo project in the `/example` folder of this repository.
+
+#### Supports: 
+* Tested from iOS 8 to iOS 11.3
+* Tested from Android 4.0.3 (API level 15) to Android 8.1 (27)