FIX: eliminate race condition creating posts

FIX: correct message bus posting

lib/distributed_mutex.rb

@@ -1,6 +1,10 @@
 # Cross-process locking using Redis.
 class DistributedMutex
 
+  def self.synchronize(key, redis=nil, &blk)
+    self.new(key, redis).synchronize(&blk)
+  end
+
   def initialize(key, redis=nil)
     @key = key
     @redis = redis || $redis