I'm using RubyMine 2016.1 and when I use the find(id) method of ActiveRecord it shows me this deprecation warning: 'ActiveRecord::Core::ClassMethods.find' call is deprecated, however, in the guide, find with primary key is not deprecated.
This seems to be a known bug in Rubymine 2016.1. You can track this bug report if you like and you can safely ignore this deprecation warning.
Update: the bug seems to be fixed now in the Rubymine 2016.1.1 security release. The IDE no longer annotates this statement as deprecated.
来源：https://stackoverflow.com/questions/36480425/activerecordcoreclassmethods-find-call-is-deprecated