title: Angular Formly: how to add class to wrapping div
body: <pre><code>&lt;formly-form model="vm.model" fields="step.inputs" options="vm.options"&gt;
      &lt;div style="text-align:right"&gt;
          &lt;button type="submit" wz-next class="btn btn-primary submit-button" ng-disabled="innerForm.$invalid"&gt;Næste&lt;/button&gt;
      &lt;/div&gt;
  &lt;/formly-form&gt;
  </code></pre>
  
  <p>Using the above markup would generate a more og less standard formly form, but my issue is that based on values set in the <code>templateOptions</code> of my fields, i want to be able to add a class to the formly-field div.</p>
  
  <p>So an example would be:</p>
  
  <pre><code>inputs: [
      {
          key: 'someKey',
          type: 'input',
          templateOptions: {
              label: 'some text',
              class: 'floatLeft'
          }
      },
      {
          key: 'someKey',
          type: 'input',
          templateOptions: {
              label: 'some text',
              class: 'floatRight'
          }
      }]
  </code></pre>
  
  <p>Should generate 2 formly-fields like these:</p>
  
  <pre><code>&lt;div formly-field ng-repeat="field in fields " class="floatLeft ..." ...&gt;...&lt;/div&gt;
  &lt;div formly-field ng-repeat="field in fields " class="floatRight ..." ...&gt;...&lt;/div&gt;
  </code></pre>
  
  <p>So the class gets added to the div, i've tried using wrappers, but they dont wrap around the formly-field div. 
  And since <code>step.inputs</code> is an array of fields, im not sure how to do it.</p>