Ruby on Rails 3.0 Release Notes: fix broken link
Merge pull request #17665 from javiervidal/fixing_documentation

Ruby on Rails 3.0 Release Notes: fix broken link
Remove call to `key?` in `LazyAttributeHash#[]`

Performance improvement, as well as improved code clarity
LazyAttributeHash is private
Remove needless call to `key?` when building attributes

This appears to be a performance hotspot, see #17655.
Make sure assert_select can assert body tag

This reverts commit f93df52845766216f0fe36a4586f8abad505cac4, reversing
changes made to a455e3f4e9dbfb9630d47878e1239bc424fb7d13.

Conflicts:
	actionpack/lib/action_controller/test_case.rb
	actionview/lib/action_view/test_case.rb
Speed up integer casting from DB

We don't have the check the range when the value is coming from the DB,
so override type_cast_from_database to short-circuit the extra work.
The difference is huge but the absolute gain is quite small. That being
said this is a hotspot and it showed up on the radar when benchmarking
discourse.
pull the preloader allocation in to a factory method
Improve the performance of reading attributes

We added a comparison to "id", and call to `self.class.primary_key` a
*lot*. We also have performance hits from `&block` all over the place.
We skip the check in a new method, in order to avoid breaking the
behavior of `read_attribute`
Duplicated Hash key :prompt
Use `Rails.application.paths['db/migrate']` for default migrations_paths