Added docs on how to remove a member

README.md

@@ -18,6 +18,7 @@ To learn more, check out:
 * Yes, it's confusing to have a `.github` and `github` directory.  That is how gitub-mgmt was originally setup an we're living with it.  (At least of 2024-09-05, there is [no backlog item for cleaning this up](https://github.com/ipdxco/github-as-code/issues?page=1&q=is%3Aissue+is%3Aopen).)
 * Not all [organization-level roles](https://docs.github.com/en/organizations/managing-peoples-access-to-your-organization-with-roles/roles-in-an-organization) are assignable through github-mgmt.  For example, organization moderators, billing managers, and ecurity managers need to set through the GitHub UI.
 * github-mgmt calls [GitHub organization owners](https://docs.github.com/en/organizations/managing-peoples-access-to-your-organization-with-roles/roles-in-an-organization#organization-owners) as "admins" in [filecoin-project.yml](https://github.com/filecoin-project/github-mgmt/blob/master/github/filecoin-project.yml).  These terms are used interchangably in comments/docs.
+* At least as of 202409, AWS resources that terraform uses behind the scenes (e.g., S3 bucket, DDB table) are all stored in an ipdx.co-managed AWS account.  
 
 ## Organization Owner SOPs
 Below is documentation/expecations [filecoin-project owners](https://github.com/orgs/filecoin-project/people?query=role%3Aowner).
@@ -39,3 +40,19 @@ Below is documentation/expecations [filecoin-project owners](https://github.com/
 > Reason: why_the_request_is_being_made  
 > Approver: who_the_approver_is  
 > App Installation Link: https://github.com/organizations/filecoin-project/settings/installations/######  
+
+### Removing Members From the Organization
+Removing members from the organization with github-mgmt has been disabled (see [here](https://github.com/filecoin-project/github-mgmt/blob/master/terraform/resources.tf)).  This is a security measure; org member removals are hard to revert because to re-invite someone, they have to accept the invitation. 
+
+To remove someone, we follow these steps:
+1. (anyone) Open a PR that removes the member from all teams and repositories and leaves a comment next to their name saying they'll be manually removed via the UI.  We do this so there is record in the commit history of the intent of the change.
+2. Get the PR approved per normal process.
+3. (github-mgmt-steward) Merge the PR.
+4. (org owner) Confrim in https://github.com/filecoin-project/github-mgmt/actions that the actions are applied.
+5. (org owner) Access the user in the GitHub UI at https://github.com/orgs/filecoin-project/people/USERNAME
+6. (org owner) Remove the user from the organization via the "Remove from organization" button.
+7. (org owner) Grab a screenshot
+8. (org owner) [Run the sync workflow](https://github.com/filecoin-project/github-mgmt/actions/workflows/sync.yml) to remove the user from the terraform state
+9. (org owner) Post back in the original PR that the user has been fully removed, including the screenshot and a link to the sync workflow run.
+
+https://github.com/filecoin-project/github-mgmt/pull/66 is an example of this process.