Migrations: report the number of rows affected when calling insert, update, delete, etc.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@6945 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/lib/active_record/migration.rb

@@ -257,6 +257,7 @@ module ActiveRecord
         result = nil
         time = Benchmark.measure { result = yield }
         say "%.4fs" % time.real, :subitem
+        say("#{result} rows", :subitem) if result.is_a?(Integer)
         result
       end