Remove removed use cases from README_transact.md

README_transact.md

@@ -50,28 +50,15 @@ end
 ```
 
 ### Update items
-An item can be updated by providing the hash key, range key if applicable, and the fields to update.
-Updating fields can also be done within a block using the `set()` method.
-To increment a numeric value or to add values to a set use `add()` within the block.
-Similarly a field can be removed or values can be removed from a set by using `delete()` in the block.
+An item can be updated by providing a model or hash key and range key if applicable, and the fields to update.
 ```ruby
 Dynamoid::TransactionWrite.execute do |txn|
-  # sets the name and title for user 1
-  # The user is found by id
-  txn.update!(User, id: 1, name: 'bob', title: 'mister')
-
-  # sets the name, increments a count and deletes a field
-  txn.update!(user) do |u| # a User instance is provided
-    u.set(name: 'bob')
-    u.add(article_count: 1)
-    u.delete(:title)
-  end
+  # change name and title for a user
+  txn.update_attributes!(user, name: 'bob', title: 'mister')
 
-  # adds to a set of integers and deletes from a set of strings
-  txn.update!(User, id: 3) do |u|
-    u.add(friend_ids: [1, 2])
-    u.delete(child_names: ['bebe'])
-  end
+  # sets the name and title for a user
+  # The user is found by id (that equals 1)
+  txn.update_fields!(User, 1, name: 'bob', title: 'mister')
 end
 ```