title: Router activeClassName in ReactJS not working
body: <p>I have a problem with router activeClassName in my React App. 
  I set my routes correctly, everything works fine. I appended activeClassName rule, when i inspect link elements they should toggle className on click, that is how activeClassName should work, but that is the problem. When i click on link element nothing happens, it do not recognize activeClassName rule, no class is applyed. </p>
  
  <p>Here are the code snippets.</p>
  
  <pre><code>import React from 'react';
  import { NavLink } from 'react-router-dom'
  import classes from './Classes.module.css'
  const navigation =(props)=&gt;{
        return(
              &lt;div&gt;
                  &lt;NavLink activeClassName={classes.Active} exact to="/"&gt;HOME&lt;/NavLink&gt;
                  &lt;NavLink activeClassName={classes.Active} exact to="/about"&gt;ABOUT&lt;/NavLink&gt;
                  &lt;NavLink activeClassName={classes.Active} exact to="/contact"&gt;CONTACT&lt;/NavLink&gt;   
              &lt;/div&gt;
  )}
  </code></pre>
  
  <p>CSS</p>
  
  <pre><code>.Active{
       background-color: red;
  }
  </code></pre>
  
  <p>Thanks !</p>