Fix missing link (#4348)

Author: filiph

src/docs/development/data-and-backend/state-mgmt/options.md

@@ -113,6 +113,7 @@ A popular library based on observables and reactions.
 [InheritedWidget docs]: {{site.api}}/flutter/widgets/InheritedWidget-class.html
 [Inheriting Widgets]: {{site.medium}}/@mehmetf_71205/inheriting-widgets-b7ac56dbbeb1
 [Introduction to Redux in Flutter]: https://blog.novoda.com/introduction-to-redux-in-flutter/
+[Introduction to state management]: /docs/development/data-and-backend/state-mgmt/intro
 [Making sense of all those Flutter Providers]: {{site.medium}}/flutter-community/making-sense-all-of-those-flutter-providers-e842e18f45dd
 [Managing Flutter Application State With InheritedWidgets]: {{site.flutter-medium}}/managing-flutter-application-state-with-inheritedwidgets-1140452befe1
 [MobX.dart, Hassle free state-management for your Dart and Flutter apps]: {{site.github}}/mobxjs/mobx.dart