Add Uno Playground

Author: yauhenipakala

README.md

@@ -228,6 +228,7 @@ Jump to
 - [FashionApp](https://github.com/devcrux/FashionApp): Design beautiful fashion app using Shell, BindableLayout, ControlTemplate and more [ Forms: iOS, Android]
 - [FlyMe](https://github.com/davidortinau/FlyMe): Sample app showcasing the use of Material Design and CollectionView within the new Shell container [ Forms: iOS, Android, UWP]
 - [FocusOnXamarin](https://github.com/jsuarezruiz/FocusOnXamarin): NET Conf: Focus on Xamarin samples [ Forms: iOS, Android]
+- [Uno Playground](https://github.com/unoplatform/Uno.Playground): Uno Gallery of components and samples [ Uno: [iOS](https://itunes.apple.com/app/uno-gallery/id1380984680), [Android](https://play.google.com/store/apps/details?id=com.nventive.uno.ui.demo), [UWP](https://www.microsoft.com/store/apps/9NTT97F69ZHZ)]
 - [Xamarin.Forms Samples](https://github.com/xamarin/xamarin-forms-samples): Official sample apps built using the Xamarin.Forms framework.
 - [more samples...](https://github.com/xamarin/mobile-samples)