diff --git a/Gemfile.lock b/Gemfile.lock
index b2d4fa4..d6fbcc3 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -114,7 +114,8 @@ GEM
       thor (>= 0.14, < 2.0)
     jquery-tablesorter (1.25.0)
       railties (>= 3.2, < 6)
-    kramdown (1.16.2)
+    kramdown (2.3.0)
+      rexml
     launchy (2.4.3)
       addressable (~> 2.3)
     loofah (2.4.0)
@@ -199,6 +200,7 @@ GEM
     responders (2.4.1)
       actionpack (>= 4.2.0, < 6.0)
       railties (>= 4.2.0, < 6.0)
+    rexml (3.2.4)
     rspec (3.7.0)
       rspec-core (~> 3.7.0)
       rspec-expectations (~> 3.7.0)