Add Gravito Id in prebid documentation (prebid#3789)

dev-docs/modules/userId.md

@@ -2375,6 +2375,36 @@ pbjs.setConfig({
 })
 ```
 
+### GRAVITO ID by Gravito Ltd.
+
+Gravito ID, provided by [Gravito Ltd.](https://gravito.net), is ID for ad targeting by using 1st party cookie.
+Please contact Gravito Ltd. for using this ID.
+
+Add the Gravito ID to your Prebid.js Package with:
+
+{: .alert.alert-info :}
+gulp build --modules=gravitoIdSystem
+
+#### Gravito ID Configuration
+
+{: .table .table-bordered .table-striped }
+| Param under userSync.userIds[] | Scope | Type | Description | Example |
+| --- | --- | --- | --- | --- |
+| name | Required | String | The name of this module | `"gravitompId"` |
+
+#### Gravito ID Example
+
+{% highlight javascript %}
+pbjs.setConfig({
+    userSync: {
+        userIds: [{
+            name: 'gravitompId'
+        }]
+    }
+});
+{% endhighlight %}
+
+
 ## Adapters Supporting the User ID Sub-Modules
 
 {% assign bidder_pages = site.pages | where: "layout", "bidder" %}

download.md

@@ -365,6 +365,9 @@ These modules may require accounts with a service provider.<br/>
   <div class="col-md-4"><div class="checkbox">
   <label><input type="checkbox" moduleCode="pubCommonIdSystem" class="bidder-check-box"> PubCommon ID<div style="font-size:80%"> (not in 5.x)</div></label>
   </div></div>
+  <div class="col-md-4"><div class="checkbox">
+  <label><input type="checkbox" moduleCode="gravitoIdSystem" class="bidder-check-box"> Gravito ID</label>
+  </div></div>
 </div>
 
 <br>