diff --git a/lib/slugtastic/model_additions.rb b/lib/slugtastic/model_additions.rb
index f5956fa..e64193c 100644
--- a/lib/slugtastic/model_additions.rb
+++ b/lib/slugtastic/model_additions.rb
@@ -1,6 +1,14 @@
 module Slugtastic
   module ModelAdditions
 
+    # To generate a slug from another value, call <tt>has_slug</tt> in any
+    # ActiveRecord model and pass in the name of the slug attribute.
+    # By default the slug will be generated from the <tt>title</tt> attribute, but
+    # you can specify by adding <tt>:from => {attribute}</tt>.
+    #
+    #   class Article < ActiveRecord::Base
+    #     has_slug :slug, :from => :title
+    #   end
     def has_slug name, options = { :from => :title }
       before_validation do |record|
         send("#{name}=", Slugtastic.generate_slug(send(options[:from]))) if send(name).nil? or send(name).blank?