1 files changed, 1 insertions, 0 deletions

diff --git a/.document b/.document
index c0c9cded79..2a76ac0705 100644
--- a/.document
+++ b/.document
@@ -13,6 +13,7 @@ rbconfig.rb
 
 trace_point.rb
 ast.rb
+io.rb
 
 # the lib/ directory (which has its own .document file)
 lib