gustly/sub_pub — pull request #2 by toddmohney (2014-10-25 23:19:51+00:00)
Title: Enable attribute-specific subscription to ActiveRecord subscribers

Allows a subscriber to subscribe to changes on specific table attributes on a model.

In the following example, ```:on_publish``` will be called only if both ```:title``` and ```:body``` are changing.
```ruby
class FakeActiveRecordBlogPostSubscriber < SubPub::ActiveRecord::Subscriber
subscribe_to(Blog::Post, 'after_update', :title, :body)

def on_publish
# do stuff
end
end
```
Any number of other table attributes may change along with ```:title``` and ```:body``` and ```:on_publish``` will still be invoked.