title: Vuetify v-autocomplete onchange event inside a v-for
body: <p>I have a <code>&lt;v-autocomplete&gt;</code> dropdown in a <code>&lt;v-for&gt;</code> that I use to select the region for every office that I have in the offices list.
  The issue is that I don't understand how to pass the index value inside the <code>updateRegion</code> method to associate the current selected value with the correct office region.
  Maybe there is another way to do this, but I don't know how.</p>
  
  <p>Here's the semplified code:</p>
  
  <pre><code>&lt;template v-for="(office, index) in offices"&gt;
      &lt;v-flex xs12 class="mt-3" :key="index"&gt;
          &lt;v-card class="white--text"&gt;
              &lt;v-card-text&gt;
                  &lt;v-layout row wrap&gt;
                      &lt;v-flex xs12 sm4 pr-2&gt;
                          &lt;v-autocomplete
                              :value="office.region.id"
                              :items="regions"
                              :label="Region"
                              @change="updateRegion"
                          &gt;&lt;/v-autocomplete&gt;
                      &lt;/v-flex&gt;
                  &lt;/v-layout&gt;
              &lt;/v-card-text&gt;
          &lt;/v-card&gt;
      &lt;/v-flex&gt;
  &lt;/template&gt;
  
  &lt;script&gt;
      methods: {
          updateRegion(value) {
              // how can I have here the index value?
          }
      }
  &lt;/script&gt;
  </code></pre>