I found it strange that this guide is redirecting questions to a specific person. Heiko Webers' (@hawe) last blog post is a year and a half old, so it's not obvious that he's still active with Rails security. If he is, feel free to revert.

the new guide

Documentation fix in options_for_select helper. Fixed display errors caused by mixing Ruby and HTML code inside the same pre tag [ci skip]

This reverts commit c3954bae.

Add documention for utc_offset method

JSON: Encode infinite or NaN floats as `null` to generate valid JSON.

notify_observers should be public

Allow extra arguments for Observers

1. ActiveRecord::Base is not ActiveRecord::Relation
2. The order of records from an SQL query is uncertain without an ORDER clause
3. Run your own tests when submitting a pull request