title: ERROR [Vue warn]: option "el" can only be used during instance creation with the `new` keyword
body: <p>I have the following abbreviated vue component:</p>
  
  <pre><code>    &lt;template&gt;
      &lt;section&gt;
          &lt;v-card class="mx-auto" color="#26c6da" dark max-width="1200"&gt;
          &lt;v-carousel &gt;
              &lt;v-carousel-item v-for="(item,i) in items" :key="i" v-html="item.content"&gt; &lt;/v-carousel-item&gt;
          &lt;/v-carousel&gt;
          &lt;/v-card&gt;
      &lt;/section&gt;
      &lt;/template&gt;
  
  
      &lt;script&gt;
      ...........................
      console.log(res);
      export default {
          el: '#app',
          data: function() {
          return {
              items: res
          };
          }
      };
      &lt;/script&gt;
  
      &lt;style scoped&gt;
      #app iframe {
          width: 100%;
          height: 500px;
      }
      &lt;/style&gt;
  </code></pre>
  
  <p>I want to add the css at the bottom to control the carousel appearance. To do this I tried to declare the 'el' property and hang the css on that. I;m getting the error in the title. How do I fix this?</p>