diff --git a/Gemfile.lock b/Gemfile.lock
index 7a391b4..87b8fa7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -57,7 +57,8 @@ GEM
     rb-fsevent (0.10.4)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.5)
+    rexml (3.3.3)
+      strscan
     rouge (3.3.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
@@ -65,7 +66,7 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    wdm (0.1.1)
+    strscan (3.1.0)
 
 PLATFORMS
   ruby
@@ -80,7 +81,6 @@ DEPENDENCIES
   kramdown
   kramdown-parser-gfm
   rouge
-  wdm (>= 0.1.0)
 
 BUNDLED WITH
    2.4.21