Merge pull request #121 from thomasklemm/master

Readme: Add instructions on limiting fields

README.md

@@ -87,6 +87,26 @@ audit.action # => "update"
 audit.audited_changes # => {"name"=>["Steve", "Ryan"]}
 ```
 
+### Specifying columns
+
+By default, a new audit is created for any attribute changes. You can, however, limit the columns to be considered.
+
+```ruby
+class User < ActiveRecord::Base
+ # All fields
+ # audited
+
+ # Single field
+ # audited only: :name
+
+ # Multiple fields
+ # audited only: [:name, :address]
+
+ # All except certain fields
+ # audited except: :password
+end
+```
+
 ### Comments
 
 You can attach comments to each audit using an `audit_comment` attribute on your model.