Add documentation around migrating records to the ghost user after user deletion.

doc/profile/README.md

@@ -2,3 +2,4 @@
 
 - [Preferences](../user/profile/preferences.md)
 - [Two-factor Authentication (2FA)](../user/profile/account/two_factor_authentication.md)
+- [Deleting your account](../user/profile/account/delete_account.md)

doc/user/profile/account/delete_account.md

+# Deleting a User Account
+
+- As a user, you can delete your own account by navigating to **Settings** > **Account** and selecting **Delete account**
+- As an admin, you can delete a user account by navigating to the **Admin Area**, selecting the **Users** tab, selecting a user, and clicking on **Remvoe user**
+
+## Associated Records
+
+> Introduced for issues in [GitLab 9.0][ce-7393], and for merge requests, award emoji, notes, and abuse reports in [GitLab 9.1][ce-10467].
+
+When a user account is deleted, not all associated records are deleted with it. Here's a list of things that will not be deleted:
+
+- Issues that the user created
+- Merge requests that the user created
+- Notes that the user created
+- Abuse reports that the user reported
+- Award emoji that the user craeted
+
+
+Instead of being deleted, these records will be moved to a system-wide "Ghost User", whose sole purpose is to act as a container for such records.
+
+
+[ce-7393]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7393
+[ce-10467]: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10467
+
+