allow planned_event role to add guests

src/model/tripdetails.rs

@@ -138,7 +138,7 @@ ORDER BY day;",
 
     pub(crate) async fn user_allowed_to_change(&self, db: &SqlitePool, user: &User) -> bool {
         if self.belongs_to_event(db).await {
-            user.has_role(db, "admin").await
+            user.has_role(db, "planned_event").await
         } else {
             self.user_is_cox(db, user).await != CoxAtTrip::No
         }