chore: add angular usage example to qr readme (#119)

Author: Silureth

packages/nativescript-qr/README.md

@@ -6,7 +6,28 @@ npm install @nstudio/nativescript-qr
 
 ## Usage
 
-// TODO
+### Angular
+
+Component / Module:
+```typescript
+import { Image } from "@nativescript/core";
+import { Qr } from "@nstudio/nativescript-qr";
+export class YourComponent{
+...
+  onImageLoaded(args) {
+    const image = args.object as Image;
+    const result = Qr.generate('Hello World');
+    image.imageSource = result;
+  }
+...
+}
+```
+
+View:
+
+```html
+  <Image src="" (loaded)="onImageLoaded($event)"></Image>
+```
 
 ## License