changed classNames to list

misago/emberapp/app/components/qacaptcha-field.js

@@ -2,7 +2,7 @@ import Ember from 'ember';
 import FormRow from 'misago/components/form-row';
 
 export default FormRow.extend({
-  classNames: 'form-group form-captcha',
+  classNames: ['form-group', 'form-captcha'],
   captcha: Ember.inject.service('qacaptcha'),
   model: Ember.computed.alias('captcha.model'),