Doc: Let OmniAuth support DingTalk

doc/integration/ding_talk.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
+---
+
+# DingTalk OAuth 2.0 OmniAuth provider **(FREE SELF)**
+
+You can sign in to GitLab using your DingTalk account.
+Sign in to DingTalk Open Platform and create an application on it. DingTalk generates a client ID and secret key for you to use.
+
+1. Sign in to [DingTalk Open Platform](https://open-dev.dingtalk.com/).
+
+1. On the top bar, select **Application development > Enterprise internal development** and then select **Create Application**.
+
+   ![DingTalk menu](img/ding_talk_menu.png)
+
+1. Fill in the application details:
+
+   - **Application Name**: This can be anything. Consider something like `<Organization>'s GitLab`, or `<Your Name>'s GitLab`, or something else descriptive.
+   - **Application Description**: Create a description.
+   - **Application icon**: Upload qualified icons if needed.
+
+   ![DingTalk create application](img/ding_talk_create_application.png)
+
+1. Select **Confirm and create**.
+
+1. On the left sidebar, select **DingTalk Application** and find your application. Select it and go to the application information page.
+
+   ![DingTalk your application](img/ding_talk_your_application.png)
+
+1. Under the **Application Credentials** section, there should be an AppKey and AppSecret (see the screenshot). Keep this page open as you continue the configuration.
+
+   ![DingTalk credentials](img/ding_talk_credentials.png)
+
+1. On your GitLab server, open the configuration file.
+
+   For Omnibus package:
+
+   ```shell
+   sudo editor /etc/gitlab/gitlab.rb
+   ```
+
+   For installations from source:
+
+   ```shell
+   cd /home/git/gitlab
+
+   sudo -u git -H editor config/gitlab.yml
+   ```
+
+1. See [Configure initial settings](omniauth.md#configure-initial-settings) for initial settings.
+
+1. Add the provider configuration:
+
+   For Omnibus package:
+
+   ```ruby
+     gitlab_rails['omniauth_providers'] = [
+       {
+         "name" => "ding_talk",
+         "app_id" => "YOUR_APP_ID",
+         "app_secret" => "YOUR_APP_SECRET"
+       }
+     ]
+   ```
+
+   For installations from source:
+
+   ```yaml
+   - { name: 'ding_talk',
+       app_id: 'YOUR_APP_ID',
+       app_secret: 'YOUR_APP_SECRET' }
+   ```
+
+1. Change `YOUR_APP_ID` to the AppKey from the application information page in step 6.
+
+1. Change `YOUR_APP_SECRET` to the AppSecret from the application information page in step 6.
+
+1. Save the configuration file.
+
+1. [Reconfigure](../administration/restart_gitlab.md#omnibus-gitlab-reconfigure) or [restart GitLab](../administration/restart_gitlab.md#installations-from-source) for the changes to take effect if you installed GitLab via Omnibus or from source respectively.

doc/integration/omniauth.md

@@ -28,6 +28,7 @@ GitLab supports the following OmniAuth providers.
 | [Azure v1](azure.md)                                                | `azure_oauth2`             |
 | [Bitbucket Cloud](bitbucket.md)                                     | `bitbucket`                |
 | [CAS](cas.md)                                                       | `cas3`                     |
+| [DingTalk](ding_talk.md)                                            | `ding_talk`                |
 | [Facebook](facebook.md)                                             | `facebook`                 |
 | [Generic OAuth 2.0](oauth2_generic.md)                              | `oauth2_generic`           |
 | [GitHub](github.md)                                                 | `github`                   |