add Github Access Structure Overview section

Contributing.md

@@ -87,6 +87,18 @@ the organizations requested. They will then close the issue.
 
 Happy triaging!
 
+## GitHub Access Structure Overview
+
+We're implementing a structured approach to GitHub permissions across our projects, ensuring clarity, security, and efficient collaboration. Each level of access is a superset of the permissions available to the level(s) below it in the hierarchy. Here’s an overview of the structure, permissions, and associated teams:
+
+* Technical Committee – admin permissions across all Express orgs ([expressjs](https://github.com/expressjs), [jshttp](https://github.com/jshttp), [pillarjs](https://github.com/pillarjs)). Highest level of access, owner permissions on repos and orgs. 
+
+* Project Captain – admin permissions on a specific repo. Permissions similar to TC, but scoped to a specific repo not an entire org. Permissions must be applied individually to a Project Captain user as a result. Creating a github team for this is optional, as the permissions are not applied at the team level.
+
+* Committer – commit bit on a given repo or repos. Permissions must be applied individually to the user. Github team here is optional, but recommended. All members of the org who have a commit bit for one or more repos can be members.
+
+* Triager – can close/tag/manage issues/discussions across all orgs. See the [Triager Guide](Triager-Guide.md) for more information. Triagers will be added to a github team in each org, and permissions will be granted to the team.
+
 ## Becoming a Committer
 
 All contributors who land a non-trivial contribution should be on-boarded in a timely manner,