docs: update readme with key features

README.md

@@ -2,6 +2,30 @@
 
 vue-paint is a simple and lightweight paint component for vue projects. It can be used to add annotations to images, videos, or just draw some simple shapes to a canvas-like area.
 
+Demo: [https://github.com/robertrosman/vue-paint]
+
+## Key features
+
+### Tree shakable
+
+Only include the tools you need and leave the rest outside of your bundle.
+
+### Non-destructive
+
+Support for both undo and redo, even after result is exported.
+
+### Clean format
+
+The state is a simple javascript array of objects you can serialize to JSON, manipulate programmatically, store in your database or local storage.
+
+### Easily extendable
+
+Create your own tools if you want to extend the library. 
+
+### Type safe
+
+Written in Typescript and fully typed.
+
 
 ## Project Setup
 
@@ -26,3 +50,7 @@ npm run build
 ```sh
 npm run lint
 ```
+
+## Contribute
+
+Contributions are welcome! Fork and create a new Pull request. Try to follow the patterns in `src/composables/tools` when creating new tools.