Update README.md

Document the changes that were made in the pull request:
https://github.com/collectiveidea/delayed_job/pull/168/files

Looking at the code in that PR I figured that the max_attempts needs to be set on the payload and I tried setting it on the custom job and it worked as expected. This feature is indeed very useful and hopefully this is well-documented and maintained in future releases. Greatly appreciate this gem!

A question - would this work with the object.delay.some_method usage. Didn't seem like it would since the DB table does not have the max_attempts as a column.

README.md

@@ -229,6 +229,19 @@ end
 
 Delayed::Job.enqueue NewsletterJob.new('lorem ipsum...', Customers.find(:all).collect(&:email))
 ```
+To set a per-job max attempts that overrides the Delayed::Worker.max_attempts you can define a max_attempts method on the job
+```ruby
+class NewsletterJob < Struct.new(:text, :emails)
+  def perform
+    emails.each { |e| NewsletterMailer.deliver_text_to_email(text, e) }
+  end
+
+  def max_attempts
+    return 3
+  end
+end
+````
+
 
 Hooks
 =====