Fixed type of grouped_products, closes #57

Author: claudiosanches

source/includes/wp-api-v1/_products.md

@@ -65,7 +65,7 @@ The products API allows you to create, view, update, and delete individual, or a
 | `attributes`         | array     | List of attributes. See [Attributes properties](#attribute-properties).                                                                                                                                                                                                                                                                                       |
 | `default_attributes` | array     | Defaults variation attributes, used only for variations and pre-selected attributes on the frontend. See [Default Attributes properties](#default-attribute-properties).                                                                                                                                                                                      |
 | `variations`         | array     | List of variations. See [Variations properties](#variation-properties)                                                                                                                                                                                                                                                                                        |
-| `grouped_products`   | string    | List of grouped products ID, only for `group` type products. <i class="label label-info">read-only</i>                                                                                                                                                                                                                                                        |
+| `grouped_products`   | array     | List of grouped products ID, only for `group` type products. <i class="label label-info">read-only</i>                                                                                                                                                                                                                                                        |
 | `menu_order`         | integer   | Menu order, used to custom sort products.                                                                                                                                                                                                                                                                                                                     |
 
 ### Download properties ###