Added scratcher widget

Added scratcher widget created by @vintage which enables the content …

Author: Robert Felker

source.md

@@ -148,6 +148,7 @@ If you appreciate the content 📖, support projects visibility, give 👍| ⭐|
 - [Rubber Bottom Sheet](https://github.com/mcrovero/rubber) <!--stargazers:mcrovero/rubber--> - Elastic material bottom sheet by [Mattia Crovero](https://github.com/mcrovero).
 - [Direct Select](https://github.com/LanarsInc/direct-select-flutter) - Selection widget with an ethereal, full-screen modal popup by [Ivan Yatsouba](https://github.com/iyatsouba).
 - [Before After](https://github.com/xsahil03x/before_after) <!--stargazers:xsahil03x/before_after--> - Beautiful slider which makes it easier to display the difference between two images, by [Sahil Kumar](https://github.com/xsahil03x).
+- [Scratcher](https://github.com/vintage/scratcher) <!--stargazers:vintage/scratcher--> - Scratch card widget which temporarily hides content from user, by [Kamil Rykowski](https://github.com/vintage).
 
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