README.md in spidey-mongo-0.0.3 vs README.md in spidey-mongo-0.0.4

@@ -44,15 +44,18 @@
 
 (The base implementation's `max_urls` parameter is also useful for this purpose.)
 
 ### Recording Results
 
-By default, invocations of `record(data)` by the spider simply insert new documents into the result collection. If corresponding results may already exist in the collection and should instead be updated, use the `set_result_key` helper (with a proc or method symbol) to specify how to find the document to update:
+By default, invocations of `record(data)` by the spider simply insert new documents into the result collection. If corresponding results may already exist in the collection and should instead be updated, define a `result_key` method that returns a key by which to find the corresponding document. The method is called with a hash of the data being recorded:
 
     class EbaySpider < Spidey::AbstractSpider
       include Spidey::Strategies::Mongo
-      set_result_key ->(data) { data[:auction_id] }
       
+      def result_key(data)
+        data[:detail_url]
+      end
+
       # ...
     end
 
 This performs an `upsert` instead of the usual `insert` (i.e., an update if a result document matching the key already exists, or insert otherwise).
 
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