title: I got an issue in using moment function in nuxtjs
body: <p>I recently used moment function of js to vue.
  But it's not working.
  It is saying that moment is not defined.
  I looked for a solution in here but any of them didn't work for me.
  How can I use moment in nuxt?</p>
  
  <pre><code>&lt;script&gt;
  import moment from "moment";
  export default {
  ...
  computed:{
      calendarWeekdays:function(){
          var n=moment.weekdays();
          return n.push(n.shift()),n;
      },
  ...
  </code></pre>
  
  <p>And the error I got is:</p>
  
  <pre><code>ERROR in ./components/DatePicker.vue?vue&amp;type=script&amp;lang=js&amp; (./node_modules/babel-loader/lib??ref--2-0!./node_modules/vue-loader/lib??vue-loader-options!./components/DatePicker.vue?vue&amp;type=script&amp;lang=js&amp;)
  </code></pre>
  
  <p>Do I have to install moment npm?</p>