title: Vuetify Form Validation - defining ES6 rules for matching inputs
body: <p>I have a (Vuetify) form with an email input that uses ES6 &amp; regex to check if it's a valid email. How would I set up another <code>emailConfirmationRules</code> ruleset to check if the <code>emailConfirmation</code> input matches the <code>email</code> input?</p>
  
  <pre><code>&lt;template&gt;
    &lt;v-form v-model="valid"&gt;
         &lt;v-text-field label="Email Address"
              v-model="email" 
              :rules="emailRules"
              required&gt;&lt;/v-text-field&gt;
  
         &lt;v-text-field label="Confirm Email Address"
              v-model="emailConfirmation" 
              :rules="emailConfirmationRules"
              required&gt;&lt;/v-text-field&gt;
     &lt;/v-form&gt;
   &lt;template&gt;
  
  export default {
      data () {
        return {
           valid: false,
           email: '',
           emailConfirmation: '',
           emailRules: [
               (v) =&gt; !!v || 'E-mail is required',
               (v) =&gt; /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/.test(v) || 'E-mail must be valid'
          ],
          emailConfirmationRules: [
              (v) =&gt; !!v || 'Confirmation E-mail is required',
          ]   (v) =&gt; ??? || 'Confirmation E-mail does not match'
      }
  }
  </code></pre>