Adding non-blocking sample

Author: taganaka

README.md

@@ -49,6 +49,11 @@ queue.process(false, 15) do |message|
   puts "'#{message}'" 
 end
 
+# Process messages in a non blocking-way
+# A soon as the queue is empty, the block will exit
+queue.process(true) do |message|
+  puts "'#{message}'" 
+end
 ```
 Contributing to redis-queue
 ----------------

example/non-blocking.rb

@@ -0,0 +1,10 @@
+require "redis-queue"
+
+redis = Redis.new
+
+queue = Redis::Queue.new('__test', 'bp__test', :redis => redis)
+queue.clear true
+
+100.times { queue << rand(100) }
+
+queue.process(true) {|m| puts m}