diff --git a/Gemfile.lock b/Gemfile.lock
index 5486ac5..17246e0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -17,7 +17,8 @@ GEM
     haml (5.0.4)
       temple (>= 0.8.0)
       tilt
-    kramdown (2.1.0)
+    kramdown (2.3.1)
+      rexml
     mustermann (1.0.3)
     rack (2.0.7)
     rack-protection (2.0.5)
@@ -25,6 +26,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
+    rexml (3.2.4)
     ruby-graphviz (1.2.4)
     sass (3.7.4)
       sass-listen (~> 4.0.0)