added detail about using tag property to modify fieldset element

Author: zoul0813

groups.md

@@ -39,4 +39,10 @@ would produce (simplified) HTML output something like this:
     <label>Age</label>
     <input type="number" />
 </fieldset>
+```
+
+You can change the default `fieldset` tag by passing the `tag` property to the `<vue-form-genator />` component in your markup.
+
+```html
+<vue-form-generator tag="div" :model="model" :schema="schema" :options="options"></vue-form-generator>
 ```