README.md in sidekiq-throttled-0.10.0 vs README.md in sidekiq-throttled-0.11.0

@@ -57,9 +57,41 @@
     # ...
   end
 end
 ```
 
+### Observer
+
+You can specify an observer that will be called on throttling. To do so pass an
+`:observer` option with callable object:
+
+``` ruby
+class MyWorker
+  include Sidekiq::Worker
+  include Sidekiq::Throttled::Worker
+
+  MY_OBSERVER = lambda do |strategy, *args|
+    # do something
+  end
+
+  sidekiq_options :queue => :my_queue
+
+  sidekiq_throttle({
+    :concurrency => { :limit => 10 },
+    :threshold   => { :limit => 100, :period => 1.hour }
+    :observer    => MY_OBSERVER
+  })
+
+  def perform(*args)
+    # ...
+  end
+end
+```
+
+Observer will receive `strategy, *args` arguments, where `strategy` is a Symbol
+`:concurrency` or `:threshold`, and `*args` are the arguements that were passed
+to the job.
+
 
 ### Dynamic throttling
 
 You can throttle jobs dynamically with `:key_suffix` option: