Rename update_attributes method to update, keep update_attributes as an alias
Change docs to use update instead of update_attributes
Change guides to use update instead of update_attributes
Updating default application templates to use update instead of update_attributes
Add Changelog entry regarding update_attibutes being renamed to update
Merge pull request #8705 from amparo-luna/change_update_attributes_to_update

Rename update_attributes method to update
Adding Back Rails::Engine::Railties#engines

Removing it breaks functionality with gems such as Thinking Sphinx.
This restores it with a deprecation warning. Closes #8551