diff --git a/gunrock/docs/Gemfile.lock b/gunrock/docs/Gemfile.lock
index 91f654c..1ef6cf7 100644
--- a/gunrock/docs/Gemfile.lock
+++ b/gunrock/docs/Gemfile.lock
@@ -91,7 +91,7 @@ GEM
       activesupport (>= 3.1)
     parallel (1.10.0)
     public_suffix (2.0.5)
-    rack (2.0.6)
+    rack (2.2.3)
     rb-fsevent (0.9.8)
     rb-inotify (0.9.8)
       ffi (>= 0.5.0)