diff --git a/Gemfile.lock b/Gemfile.lock
index b0fd187..33fd065 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -45,7 +45,8 @@ GEM
     http-accept (1.7.0)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
-    kramdown (1.5.0)
+    kramdown (2.3.0)
+      rexml
     mime-types (3.3.1)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2019.1009)
@@ -61,6 +62,7 @@ GEM
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
+    rexml (3.2.4)
     rspec (3.0.0)
       rspec-core (~> 3.0.0)
       rspec-expectations (~> 3.0.0)