feat(form-plugin): add ability to work with string field for select2

site/plugins/form/app/Controllers/FormController.php

@@ -535,6 +535,8 @@ class FormController extends Controller
         $name    = isset($properties['name'])  ? $properties['name'] : $field_name;
         $current_value   = isset($properties['value']) ? $properties['value'] : $field_value;
 
+        $current_value = array_map('trim', explode(',', $current_value));
+
         return $this->flextype['view']->fetch('plugins/form/templates/fields/tags/field.html', ['title' => $title, 'size' => $size, 'name' => $name, 'id' => $id, 'class' => $class, 'help' => $help , 'options' => $options, 'current_value' => $current_value]);
     }
 

site/plugins/form/templates/fields/tags/field.html

@@ -1,11 +1,12 @@
 <div class="form-group {{ size }}">
     <label for="{{ id }}" class="form-control-title">{{ tr(title) }}</label>
-    <select class="{{ class }} js-tags" name="{{ name }}[]" multiple="multiple">
+    <select class="{{ class }} js-tags" data-name="{{ name }}" multiple="multiple">
         {% for key, value in current_value %}
             <option value="{{ value }}" selected="selected">{{ value }}</option>
         {% endfor %}
     </select>
+    <input type="hidden" name="{{ name }}" value="{{ current_value|join(',') }}">
     {% if help %}
         <small>{{ help }}</small>
     {% endif %}
-</div>
+</div>