! Fix class including a module with Memoizable raises error

[PikachuEXE]

My project uses "concern module pattern"

e.g. multiple controller classes including concern modules with instance methods cached

I am switching from memoist since it's officially unmaintained

[flash-gordon]

Excuse my ignorance but what is "concern module pattern"? :) Why is this patch needed? At first glance, I don't feel comfortable with having a workaround for a misused ruby API.

[PikachuEXE]

A brief example:

require "dry/core/memoizable"

module WithBotDetection
  include Dry::Core::Memoizable

  def self.included(base)
    # Do something custom
  end

  def is_bot?(something = false)
    # ...
  end
  memoize :is_bot?
end

class Controller1
  include WithBotDetection
end

class Controller2
  include WithBotDetection
end

Controller1.new.is_bot? # => NoMethodError: undefined method `key?' for nil:NilClass

Due to #61 only happens to methods with arguments

More about "concern module pattern":
https://api.rubyonrails.org/classes/ActiveSupport/Concern.html