Merge pull request #347 from OneSignal/feat/offline_readme

Added offline readme.md

Author: jkasten2

OneSignalExample/Assets/OneSignal/README.md

@@ -0,0 +1,35 @@
+## OneSignal Push Notifications
+[OneSignal](https://www.onesignal.com) is a free push notification service for Android and iOS apps. This SDK makes it easy to integrate your Unity app with OneSignal.
+
+### Supported Platforms
+#### Devices
+* iOS 9 - 14
+* Android 4.0.3 (API Level 15) - Android 11 (API Level 30)
+* Amazon FireOS 3 - 6
+
+#### Unity Versions
+* Unity 2018.4, 2019.4, and 2020.2
+
+### Quick setup
+Add the following code to a script that starts with your game or app.
+```C#
+  // Replace 'YOUR_ONESIGNAL_APP_ID' with your OneSignal App ID from app.onesignal.com
+  OneSignal.StartInit("YOUR_ONESIGNAL_APP_ID").EndInit();
+```
+
+### Demo Project
+Try out the OneSignalExampleScene scene on a device (iOS or Android) and check out the code for it in the GameControllerExample.cs file under the Examples folder.
+
+### Installation and Setup
+See the [Setup Guide](https://documentation.onesignal.com/docs/unity-sdk-setup) for installation and setup instructions.
+
+### API
+See OneSignal's [Unity SDK API](https://documentation.onesignal.com/docs/unity-sdk) page for a list of all available methods.
+
+### Change Log
+See this repository's [release tags](https://github.com/OneSignal/OneSignal-Unity-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-Unity-SDK/issues) for feature requests and bug reports related specifically to the SDK.
+
+For account issues and support please contact OneSignal support from the [OneSignal.com](https://onesignal.com) dashboard.