title: Vue-Cookies: this.$cookies is undefined
body: <p>In my main component I have:</p>
  
  <pre><code>mounted() {
      window.$cookie.set('cookie_name', userName, expiringTime);
  },
  </code></pre>
  
  <p>This yields the following error:</p>
  
  <blockquote>
    <p>Error in mounted hook: "TypeError: Cannot read property 'set' of
    undefined"</p>
  </blockquote>
  
  <p>In my <code>main.js</code> I have:</p>
  
  <pre><code>import VueCookies from 'vue-cookies';
  Vue.use(VueCookies);
  </code></pre>
  
  <p>Any idea?</p>