title: how to v-model for array of objects
body: <p>I have and array of objects, this is indefinite array, may push or splice things here. I need to bind the property of an object to a input dom with vue, doesnt seem to work.</p>
  
  <h1>heres the data</h1>
  
  <pre><code>   items : [
       { prop1: 123, prop2: 'test', prop3: 'foo' },
       { prop1: 321, prop2: 'tset', prop3: 'bar' },
     ]
  
  }
  </code></pre>
  
  <h1>trying to do</h1>
  
  <pre><code>
     &lt;li v-for="item in items"&gt; 
        {{ item.prop2 }} 
        &lt;input type="text" v-model="item.prop1"&gt;
     &lt;/li&gt;
  
  &lt;/ul&gt;
  </code></pre>