Added YouTrack integration

Fixes gitlab-org/gitlab-ce#42595

1 files changed, 28 insertions, 0 deletions

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+# YouTrack Service
+
+1. To enable the YouTrack integration in a project, navigate to the
+[Integrations page](project_services.md#accessing-the-project-services), click
+the **YouTrack** service, and fill in the required details on the page as described
+in the table below.
+
+    | Field | Description |
+    | ----- | ----------- |
+    | `description`   | A name for the issue tracker (to differentiate between instances, for example) |
+    | `project_url`   | The URL to the project in YouTrack which is being linked to this GitLab project |
+    | `issues_url`    | The URL to the issue in YouTrack project that is linked to this GitLab project. Note that the `issues_url` requires `:id` in the URL. This ID is used by GitLab as a placeholder to replace the issue number. |
+    | `new_issue_url` | This is the URL to create a new issue in YouTrack for the project linked to this GitLab project. **This is currently not being used and will be removed in a future release.** |
+
+    Once you have configured and enabled YouTrack you'll see the YouTrack link on the GitLab project pages that takes you to the appropriate YouTrack project.
+
+1. To disable the internal issue tracking system in a project, navigate to the General page, expand [Permissions](../settings/index.md#sharing-and-permissions), and slide the Issues switch invalid.
+
+    ![Issue configuration](img/issue_configuration.png)
+
+## Referencing issues in YouTrack
+
+Issues in YouTrack can be referenced as `<PROJECT>-<ID>` where `<PROJECT>`
+starts with a capital letter which is then followed by capital letters, numbers
+or underscores, and `<ID>` is a number (example `API_32-143`).
+
+`<PROJECT>` part is included into issue_id and links can point any YouTrack
+project (`issues_url` + issue_id)