diff --git a/Rails/Chatroom/Gemfile.lock b/Rails/Chatroom/Gemfile.lock
index 2d038c4..bf574f0 100644
--- a/Rails/Chatroom/Gemfile.lock
+++ b/Rails/Chatroom/Gemfile.lock
@@ -92,7 +92,7 @@ GEM
       mini_portile2 (~> 2.3.0)
     popper_js (1.12.9)
     puma (3.11.4)
-    rack (2.0.4)
+    rack (2.0.8)
     rack-test (1.0.0)
       rack (>= 1.0, < 3)
     rails (5.1.6)