Add audit trigger for when invite is consumed

Invites are deleted once used, so log this in the audit table

app/src/db/migrations/20240703000000_015-invite-audit-trigger.js

@@ -0,0 +1,15 @@
+exports.up = function (knex) {
+  return Promise.resolve()
+    // Create invite audit trigger
+    .then(() => knex.schema.raw(`
+      CREATE TRIGGER audit_invite_trigger
+      AFTER UPDATE OR DELETE ON invite
+      FOR EACH ROW EXECUTE PROCEDURE audit.if_modified_func();
+    `));
+};
+
+exports.down = function (knex) {
+  return Promise.resolve()
+    // Drop invite audit trigger
+    .then(() => knex.schema.raw('DROP TRIGGER IF EXISTS audit_invite_trigger ON invite'));
+};