Update PERMISSIONS.md

Author: avivkeller

PERMISSIONS.md

@@ -25,7 +25,8 @@
 | **[Codecov][]**              | Read                               | -           | Admin                  | Admin             | Admin              | Access to this service is granted via GitHub authentication, and only related to the repository above.                       |
 | **[Crowdin][]**              | Read                               | -           | -                      | Admin             | Admin              | Credentials for a user with elevated exist in 1Password. Access to this service may be granted to outside collaborators on a case-by-case, language-by-language basis.                |
 | **[Figma][]**                | Read                               | -           | Write                  | -                 | -                  | Access to this service is controlled by the OpenJS Foundation and @avivkeller, and only covers website-related design files. |
-| **[Sentry][]**               | -                                  | -           | -                      | Admin             | Admin              |                                                                                                                              |
+| **[HackMD][]**               | -                                  | -           | -                      | -                 | Admin | |
+| **[Sentry][]**               | -                                  | -              | -                      | Admin             | Admin              |                                                                                                                              |
 | **[Vercel][]**               | -                                  | -           | -                      | Admin             | Admin              | Along with individual access, credentials for a user with elevated exist in 1Password. |
 
 ## Access Tokens & Automations
@@ -45,6 +46,7 @@
 [Codecov]: https://app.codecov.io/github/nodejs
 [Crowdin]: https://crowdin.com/project/nodejs-web
 [Figma]: https://www.figma.com/file/a10cjjw3MzvRQMPT9FP3xz
+[HackMD]: https://hackmd.io
 [nodejs/discord-status-worker]: https://github.com/nodejs/discord-status-worker
 [nodejs/doc-kit]: https://github.com/nodejs/doc-kit
 [nodejs/node.js.org]: https://github.com/nodejs/node.js.org