From 945be06edbcfdfd3ffd50362c3b2a71ad995e89a Mon Sep 17 00:00:00 2001
From: tildearrow <me@tildearrow.org>
Date: Sat, 16 Mar 2024 11:16:30 -0500
Subject: [PATCH] update contributing guidelines

---
 CONTRIBUTING.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 70d9831fa..78cce40e3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -97,6 +97,7 @@ just put your demo song in `demos/`! be noted there are some guidelines:
 - the following systems are not acceptable:
   - YMU759/MA-2: exists only for compatibility.
   - Pong: it is a joke system.
+- the song shall be in Furnace file format.
 
 # Finishing