Clarify time-traveling (#1525)

* Clarify time-travelling

* Update linked file based on comments

Author: phanan

src/v2/guide/state-management.md

@@ -6,7 +6,7 @@ order: 502
 
 ## Official Flux-Like Implementation
 
-Large applications can often grow in complexity, due to multiple pieces of state scattered across many components and the interactions between them. To solve this problem, Vue offers [vuex](https://github.com/vuejs/vuex): our own Elm-inspired state management library. It even integrates into [vue-devtools](https://github.com/vuejs/vue-devtools), providing zero-setup access to time travel.
+Large applications can often grow in complexity, due to multiple pieces of state scattered across many components and the interactions between them. To solve this problem, Vue offers [vuex](https://github.com/vuejs/vuex): our own Elm-inspired state management library. It even integrates into [vue-devtools](https://github.com/vuejs/vue-devtools), providing zero-setup access to [time travel debugging](https://raw.githubusercontent.com/vuejs/vue-devtools/master/media/demo.gif).
 
 ### Information for React Developers