diff --git a/docs-book/Gemfile.lock b/docs-book/Gemfile.lock
index 2e57049..fcbb597 100644
--- a/docs-book/Gemfile.lock
+++ b/docs-book/Gemfile.lock
@@ -156,7 +156,7 @@ GEM
       activesupport (>= 3.1)
     public_suffix (3.0.3)
     puma (3.12.0)
-    rack (1.6.11)
+    rack (1.6.13)
     rack-livereload (0.3.17)
       rack
     rack-rewrite (1.5.1)