title: When I use dynamic variables for my v-model it doesn't work
body: <p>So, I have a simple form:</p>
  
  <pre><code>&lt;template v-for="form in forms"&gt;
      {{ form.header }}
      &lt;template v-for="input in form.inputs"&gt;
          &lt;label&gt;{{ input.label }}&lt;/label&gt;
          &lt;v-flex class="xs12 md6"&gt;
              &lt;input :v-model="input.key" /&gt;
          &lt;/v-flex&gt;
      &lt;/template&gt;
  
  &lt;/template&gt;
  </code></pre>
  
  <p>Which is being dynamically made from a forms data object:</p>
  
  <pre><code>forms:[
      {
          header: 'General Information',
          description: 'General Information',
          inputs: [
              {
                  label: 'First name',
                  key: 'account.firstname'
              },
          ]
      }
  </code></pre>
  
  <p>I have a pre-build account object for the v-model:</p>
  
  <pre><code>data: () =&gt; ({
      account: {
          firstname: 'Initial firstname'
      }
  })
  </code></pre>
  
  <p>But this is not working. I get no errors, but my dynamic v-model is not getting the account.firstname data. What am I missing to fix this?</p>