Resources added for RxJS (#1044)

* Resources added for RxJS

* Update content/roadmaps/100-frontend/content/111-pick-a-framework/101-angular/100-rxjs.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/100-frontend/content/111-pick-a-framework/101-angular/100-rxjs.md

@@ -1 +1,10 @@
-# Rxjs
+# RxJS
+
+RxJS (Reactive Extensions for JavaScript) is a library for reactive programming using observables that makes it easier to compose asynchronous or callback-based code.
+
+<ResourceGroupTitle>Free Content</ResourceGroupTitle>
+
+<BadgeLink colorScheme='blue' badgeText='Official Website' href='https://rxjs.dev/guide/overview'>RxJS Official Website</BadgeLink>
+<BadgeLink colorScheme='blue' badgeText='Read' href='https://angular.io/guide/rx-library'>RxJS Angular Docs</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=2LCo926NFLI'>RxJS Quick Start</BadgeLink>
+<BadgeLink colorScheme='green' badgeText='Course' href='https://www.youtube.com/watch?v=PhggNGsSQyg'>RxJS Crash Course</BadgeLink>