diff --git a/Gemfile.lock b/Gemfile.lock
index 68bf561..5e630a5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -57,7 +57,8 @@ GEM
       guard-compat (~> 1.1)
       rspec (>= 2.99.0, < 4.0)
     jaro_winkler (1.5.2)
-    kramdown (2.1.0)
+    kramdown (2.3.1)
+      rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     listen (3.0.7)
@@ -88,6 +89,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)
       ffi (~> 1.0)
+    rexml (3.2.4)
     rspec (3.8.0)
       rspec-core (~> 3.8.0)
       rspec-expectations (~> 3.8.0)