Redmine

Hi,

I'm trying to find some really updated manual for plugin development in Redmine 3, so with Rails 4.2

Is Redmine 3 support Rails 3+ gem plugins ?
How can I override models, controllers or helpers ? I read about ActiveSupport::Concern. It is the recommended way actually ?
For my old plugins I'm used the "included/extend/send ClassMethods InstanceMethods class_eval" pattern, alias_method_chain and before_filter but I read about before_action, and deprecated alias_method_chain method.

Thanks ;o)

http://www.redmine.org/projects/redmine/wiki/Plugin_Internals is not updated
http://guides.rubyonrails.org/plugins.html don't talk about override, just extends