title: remove option from second select if already selected [Ordered multiple selection]
body: <p>I had select option repeater.</p>
  
  <p>What I want is that when I selected johndoe at the first option, it will no longer display on the second select option.</p>
  
  <p>here's my html </p>
  
  <pre><code>&lt;div id="app"&gt;
    &lt;h1&gt;Vue JS Multiple Fields Repeater&lt;/h1&gt;
            &lt;div class="col-sm-6"&gt;
              &lt;div class="panel panel-default relative has-absolute" v-for="(field, index) in users.usersRepeater"&gt;
                &lt;button @click="addUsersField" type="button"&gt;
                  Add
                &lt;/button&gt;
                &lt;button @click="deleteUsersField(index)" v-if="field != 0" type="button"&gt;
                  Delete
                &lt;/button&gt;
                &lt;div class="panel-body has-absolute"&gt;
                  &lt;div class="form-group"&gt;
                    &lt;label for="users" class="control-label col-sm-3 text-left"&gt;Users {{field}}&lt;/label&gt;
                      &lt;select :name="'users'+index"
                        class="form-control"
                        id="users"&gt;
                          &lt;option value="" hidden&gt;Select User&lt;/option&gt;
                          &lt;option value="1"&gt;John Doe&lt;/option&gt;
                          &lt;option value="2"&gt;Mark Doe&lt;/option&gt;
                          &lt;option value="3"&gt;Mae Doe&lt;/option&gt;
                          &lt;option value="4"&gt;John Smith&lt;/option&gt;
                          &lt;option value="5"&gt;Mae Smith&lt;/option&gt;
                      &lt;/select&gt;
                  &lt;/div&gt;
                &lt;/div&gt;
              &lt;/div&gt;
            &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>here's my vue.js</p>
  
  <pre><code>new Vue({
    el: '#app',
    data: {
      users: {
            usersRepeater: [{ user: '' }]
          }
    },
    methods: {
        addUsersField: function() {
          this.users.usersRepeater.push({
            user: ''
          });
        },
        deleteUsersField: function(index) {
          this.users.usersRepeater.splice(index, 1);
        },
    }
  });
  </code></pre>
  
  <p>here's the fiddle -> <a href="https://jsfiddle.net/0e3csn5y/23/" rel="nofollow noreferrer">https://jsfiddle.net/0e3csn5y/23/</a></p>