Add a "bin/audit synchronize" command

Summary: Ref T10978. This is just a maintenance convenience script. It can fix up overall commit state after you `bin/audit delete` stuff or nuke a bunch of stuff from the database, as I did on `secure.phabricator.com`.

Test Plan: Ran `bin/audit synchronize`, and `bin/audit update-owners`.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10978

Differential Revision: https://secure.phabricator.com/D17271

src/docs/user/userguide/audit.diviner

@@ -156,6 +156,46 @@ Audit Tips
   - Press "?" to view keyboard shortcuts.
 
 
+Audit Maintenance
+=================
+
+The `bin/audit` command allows you to perform several maintenance operations.
+Get more information about a command by running:
+
+```
+phabricator/ $ ./bin/audit help <command>
+```
+
+Supported operations are:
+
+**Delete Audits**: Delete audits that match certain parameters with
+`bin/audit delete`.
+
+You can use this command to forcibly delete requests which may have triggered
+incorrectly (for example, because a package or Herald rule was configured in an
+overbroad way).
+
+After deleting audits, you may want to run `bin/audit synchronize` to
+synchronize audit state.
+
+**Synchronize Audit State**: Synchronize the audit state of commits to the
+current open audit requests with `bin/audit synchronize`.
+
+Normally, overall audit state is automatically kept up to date as changes are
+made to an audit. However, if you delete audits or manually update the database
+to make changes to audit request state, the state of corresponding commits may
+no longer be correct.
+
+This command will update commits so their overall audit state reflects the
+cumulative state of their actual audit requests.
+
+**Update Owners Package Membership**: Update which Owners packages commits
+belong to with `bin/audit update-owners`.
+
+Normally, commits are automatically associated with packages when they are
+imported. You can use this command to manually rebuild this association if
+you run into problems with it.
+
 Next Steps
 ==========