Use :manual_ack as a more descriptive name

Author: Michael Klishin

ruby/worker.rb

@@ -13,7 +13,7 @@
 puts " [*] Waiting for messages. To exit press CTRL+C"
 
 begin
-  q.subscribe(:ack => true, :block => true) do |delivery_info, properties, body|
+  q.subscribe(:manual_ack => true, :block => true) do |delivery_info, properties, body|
     puts " [x] Received '#{body}'"
     # imitate some work
     sleep 1.0