diff --git a/LTI-Introduction/Gemfile.lock b/LTI-Introduction/Gemfile.lock
index d7133a2..b36f906 100644
--- a/LTI-Introduction/Gemfile.lock
+++ b/LTI-Introduction/Gemfile.lock
@@ -96,7 +96,7 @@ GEM
     nokogiri (1.10.4)
       mini_portile2 (~> 2.4.0)
     public_suffix (3.0.2)
-    rack (2.0.8)
+    rack (2.2.3)
     rack-test (0.8.2)
       rack (>= 1.0, < 3)
     rails (5.1.4)