Doc fix (closes #4014) [thijs@fngtps.com]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@3741 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/calculations.rb

@@ -87,7 +87,7 @@ def maximum(column_name, options = {})
 
       # Calculates the sum value on a given column.  The value is returned with the same data type of the column..  See #calculate for examples with options.
       #
-      #   Person.maximum('age')
+      #   Person.sum('age')
       def sum(column_name, options = {})
         calculate(:sum, column_name, options)
       end