diff --git a/lib/resque_cleaner/server.rb b/lib/resque_cleaner/server.rb
index <HASH>..<HASH> 100644
--- a/lib/resque_cleaner/server.rb
+++ b/lib/resque_cleaner/server.rb
@@ -1,3 +1,5 @@
+require 'yaml'
+
 # Extends Resque Web Based UI.
 # Structure has been borrowed from ResqueScheduler.
 module ResqueCleaner
resque <I> seems requiring yaml