Feature(integrate zentao): part of Documentation

doc/user/project/integrations/overview.md

@@ -60,6 +60,7 @@ Click on the service links to see further configuration instructions and details
 | [Unify Circuit](unify_circuit.md)                         | Receive events notifications.                                                                | **{dotted-circle}** No |
 | [Webex Teams](webex_teams.md)                             | Receive events notifications.                                                                | **{dotted-circle}** No |
 | [YouTrack](youtrack.md)                                   | Use YouTrack as the issue tracker.                                                           | **{dotted-circle}** No |
+| [ZenTao](zentao.md)                                       | Use ZenTao as the issue tracker.                                                           | **{dotted-circle}** No |
 
 ## Push hooks limit
 

doc/user/project/integrations/zentao.md

+---
+stage: Ecosystem
+group: Integrations
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# ZenTao product integration **(PREMIUM)**
+
+[ZenTao](https://www.zentao.net/) is a web-based project management platform.
+
+## Configure ZenTao
+
+This integration requires a ZenTao API secret key.  
+
+Complete these steps in ZenTao:  
+
+1. Go to your **Admin** page and select **Develop > Application**.
+1. Select **Add Application**.
+1. Under **Name** and **Code**, enter a name and a code for the new secret key.
+1. Under **Account**, select an existing account name.
+1. Select **Save**.
+1. Copy the generated key to use in GitLab.
+
+## Configure GitLab
+
+Complete these steps in GitLab:
+
+1. Go to your project and select **Settings > Integrations**.
+1. Select **ZenTao**.
+1. Turn on the **Active** toggle under **Enable Integration**.
+1. Provide the ZenTao configuration information:
+   - **ZenTao Web URL**: The base URL of the ZenTao instance web interface you're linking to this GitLab project (for example, `example.zentao.net`).
+   - **ZenTao API URL** (optional): The base URL to the ZenTao instance API. Defaults to the Web URL value if not set.  
+   - **ZenTao API token**: Use the key you generated when you [configured ZenTao](#configure-zentao).
+   - **ZenTao Product ID**: To display issues from a single ZenTao product in a given GitLab project. The Product ID can be found in the ZenTao product page under **Settings > Overview**.
+
+   ![ZenTao settings page](img/zentao_product_id.png)
+
+1. To verify the ZenTao connection is working, select **Test settings**.
+1. Select **Save changes**.