📝 document the configuration file

Author: JoshuaTheMiller

README.md

@@ -4,9 +4,21 @@ Groups (currently Azure Active Directory Only) to GitHub Teams sync
 
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-## Some Sparse Documentation (to be updated)
+## Configuration File
 
-## Configuration of this tool
+This service/Action requires that a configuration file be present in the `.github` repository of your GitHub Organization. An example of this is show below:
+
+Filename: `team-sync-options.yaml`
+```yaml
+# This property is used to control the addition of general Members to your Organization.
+OrganizationMembersGroup: Some_Group_To_Sync_For_Organization_Membership
+# This property is used for syncing all other GitHub Teams. Please note that users must also be a part of the `OrganizationMembersGroup` for the synchronization of the teams below to function properly.
+GitHubTeamNames:
+- Some_Team_To_Sync
+- Some_Other_Team_To_Sync
+```
+
+## Necessary configuration of the tool/service
 
 As of this writing, this sync tool can be ran as a standalone app, or as a GitHub Action.