diff --git a/examples/demo_app-rails5/Gemfile.lock b/examples/demo_app-rails5/Gemfile.lock
index 6e16602..6747fc9 100644
--- a/examples/demo_app-rails5/Gemfile.lock
+++ b/examples/demo_app-rails5/Gemfile.lock
@@ -115,7 +115,7 @@ GEM
     puma (4.3.12)
       nio4r (~> 2.0)
     racc (1.6.0)
-    rack (2.2.3)
+    rack (2.2.3.1)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (5.2.7)