Add navigation guards question

Author: sudheerj

README.md

@@ -227,6 +227,8 @@ List of 300 VueJS Interview Questions
 |218| [What is the purpose of comments option?](#what-is-the-purpose-of-comments-option)|
 |219| [How to identify whether code is running on client or server?](#how-to-identify-whether-code-is-running-on-client-or-server)|
 |220| [How do you watch route object changes?](#how-do-you-watch-route-object-changes)|
+|221| [How do you sync current route in vuex store?](#how-do-you-sync-current-route-in-vuex-store)|
+|222| [What are navigation guards in vue router?](#what-are-navigation-guards-in-vue-router)|
 
 1. ### What is VueJS?
  **Vue.js** is an open-source, progressive Javascript framework for building user interfaces that aim to be incrementally adoptable. The core library of VueJS is focused on the `view layer` only, and is easy to pick up and integrate with other libraries or existing projects.
@@ -3984,3 +3986,23 @@ List of 300 VueJS Interview Questions
  }
  }
  ```
+221. ### How do you sync current route in vuex store?
+ You can use `vue-router-sync` library to sync current $route object in vuex store's state. The usage is quite straight forward with two steps
+ 1. **Installation:**
+ ```bash
+ npm install vuex-router-sync
+ ```
+ 2. **Sync router and store:**
+ ```javascript
+ import { sync } from 'vuex-router-sync'
+ import store from './vuex/store' // vuex store instance
+ import router from './router' // vue-router instance
+
+ const unsync = sync(store, router) // Returns an unsync callback function
+ unsync() // Unsyncs store from router
+ ```
+222. ### What are navigation guards in vue router?
+ The navigation guards of vue-router are used to protect navigations either by redirecting it or canceling it. Below are the 3 different ways to hook into router navigations
+ 1. Global:
+ 2. Per-route:
+ 3. In-component: