diff --git a/Chapter12/Activity12.01/blog/Gemfile.lock b/Chapter12/Activity12.01/blog/Gemfile.lock
index 2f40482..2d1762f 100644
--- a/Chapter12/Activity12.01/blog/Gemfile.lock
+++ b/Chapter12/Activity12.01/blog/Gemfile.lock
@@ -98,7 +98,7 @@ GEM
     pg (1.1.4)
     public_suffix (4.0.1)
     puma (3.12.1)
-    rack (2.0.7)
+    rack (2.0.8)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (5.2.3)