Make sure the Monitor is require before using it

iNecas · iNecas · commit 1e0da58e7a96 · 2015-06-24T14:19:56.000+02:00
diff --git a/lib/concurrent/synchronization/monitor_object.rb b/lib/concurrent/synchronization/monitor_object.rb
@@ -1,3 +1,5 @@
+require 'monitor'
+
 module Concurrent
   module Synchronization
 
