How to make module variables that can be accessible in class and in each model instance?

I can access to module pluggins_list method through e.g. @page.plugins.pluggins_list, but if I'm trying to get Plugginable methods or variables in Plugin model by e.g. @page.page_elements.first.get_pluggin I got nil or undefined. How to make module pluggins accessable outside and also that they can be available in each Plugin instance?

Edit, better example:

[3] pry(#<Plugin>)> plg = Plugin.new(name: "nutella")
=> #<Plugin id: nil, element_type: "Plugin", name: "nutella", page_id: nil>
[4] pry(#<Plugin>)> plg.get_pluggin
[5] pry(#<Plugin>)> plg.pluggins
=> nil
[6] pry(#<Plugin>)> pluggin_by_name(name)
NoMethodError: undefined method `find' for nil:NilClass

Current code:

module Plugginable
  extend ActiveSupport::Concern
  attr_accessor :pluggins

  included do
    @pluggins = [{name: "dupa"},{name: "hello"}]
  end

  module ClassMethods
    def pluggins_list
      @pluggins
    end
  end

  def pluggin_by_name(name)
    @pluggins.find {|plg| plg.name === name.downcase }
  end

  module InstanceMethods
  end
end

class Plugin < PageElement
  include Plugginable

  def get_pluggin
    binding.pry
    # pluggin_by_name(name)
  end
end