diff --git a/flipped-demos/ch07-bdd-cucumber/students/Gemfile.lock b/flipped-demos/ch07-bdd-cucumber/students/Gemfile.lock
index 97e81ac..035683b 100644
--- a/flipped-demos/ch07-bdd-cucumber/students/Gemfile.lock
+++ b/flipped-demos/ch07-bdd-cucumber/students/Gemfile.lock
@@ -110,7 +110,7 @@ GEM
       mini_portile2 (~> 2.1.0)
       pkg-config (~> 1.1.7)
     pkg-config (1.1.7)
-    rack (1.6.4)
+    rack (1.6.13)
     rack-test (0.6.3)
       rack (>= 1.0)
     rails (4.2.6)