title: dynamic object is changed when I modify another object VUE
body: <p>Here is the example of my problem:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="false" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>const app = new Vue({
    el: '#mainCreate',
    data: {
      v_total : 0,
      test : [],
    },
  });
  function f_test(){
    var d = [
      {title : 'p1', price : 0},
      {title : 'p2', price : 2},
      {title : 'p3', price : 0},
      {title : 'p4', price : 4}
    ]
  
    $.each(d, function(index,date){
      Vue.set(app.test, index, date);
    });
  }
  
  function changeV(){
   app.v_total += 10;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/vue/2.5.16/vue.js"&gt;&lt;/script&gt;
  &lt;script type="text/javascript" src="https://code.jquery.com/jquery-3.2.1.min.js"&gt;&lt;/script&gt;
    
  &lt;div id="mainCreate"&gt;
    &lt;h4&gt;I input the charge with a check according to a v-if, but look what happens if I select an input that was not checked and change the value of v_total .... reload the input&lt;/h4&gt;
  
    v_total = {{ v_total}}
    &lt;br&gt;
      &lt;span v-for="date in test"&gt;
        {{ date.title }}
        &lt;input type="checkbox"
               name="featuresBox"
               v-bind:checked="date.price == 0"&gt;
        &lt;br&gt;
      &lt;/span&gt;
  
      &lt;button onClick="f_test()"&gt;create object&lt;/button&gt;
      &lt;button onClick="changeV()"&gt;change app.v_total&lt;/button&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>if I just change the <code>app.v_total</code> because the input loses its <code>check</code> that I put with <code>v-if</code>? (I think it's because VUE believes that the test is also updated) and it should not be that way.</p>