title: Register local component when using vue-property-decorator
body: <p>Just learning Vue and TypeScript with class based components, my single file component looks like this:</p>
  
  <pre><code>&lt;template&gt;
      ...
      &lt;div&gt;
          &lt;contact-component v-bind:key="c.id" v-for="c in contacts"&gt;
          &lt;/contact-component&gt;
      &lt;/div&gt;
  &lt;/template&gt;
  
  &lt;script lang="ts"&gt;
  import ContactComponent from "./Contact.vue";
  import { Component, Vue } from 'vue-property-decorator'
  
  @Component
  export default class ContactsComponent extends Vue {
      data() {...}
      components = { ContactComponent }
  }
  &lt;/script&gt;
  </code></pre>
  
  <p>It generates the following error:</p>
  
  <blockquote>
    <p>Unknown custom element:  - did you register the
    component correctly?</p>
  </blockquote>
  
  <p>Obviously my registration of the component does not work, but I have no idea how to fix this in TypeScript. What's the correct way to register <code>ContactComponent</code> so that it can be used in the above template?</p>