Update Redmine::Plugin document
I want to more information to Redmine methods for plugin development.
As a trial, I created a patch to add below information to Redmine::Plugin.
- Add @since to each Redmine::Plugin methods
- Add reference to Plugin_Tutorial wiki and Redmine::Plugin#requires_redmine
- Add description to a few methods
I checked @since info with using yard diff(the result pasted below).
I will create patches to add @since information to Redmine methods after this tickets was closed.