diff --git a/Gemfile.lock b/Gemfile.lock
old mode 100755
new mode 100644
index 983d617..882b6d0
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -59,7 +59,8 @@ GEM
       listen (~> 3.0)
     katex (0.6.0)
       execjs (~> 2.7)
-    kramdown (2.1.0)
+    kramdown (2.3.1)
+      rexml
     kramdown-math-katex (1.0.1)
       katex (~> 0.4)
       kramdown (~> 2.0)
@@ -89,6 +90,7 @@ GEM
     rb-fsevent (0.10.3)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
+    rexml (3.2.4)
     rouge (3.16.0)
     rubyzip (2.2.0)
     safe_yaml (1.0.5)