Add a superclass/module for containers to allow defining containers as classes

[woarewe]

Currently, the only way to define a container is using the DSL:

Using a global container

F.define do
  namespace :hello do
    f(:world) { -> { "Hello, world!" } }
  end
end

Using a custom container

container = F::Container.new

F.define(container) do
 namespace :hello do
    f(:world) { -> { "Hello, world!" } }
  end
end

The goal is to make the following code work:

# using inheritance
class MyContainer < F::Container::DSL
  namespace :hello do
      f(:world) { -> { "Hello, world!" } }
  end
end

# or using extend, which I am leaning toward most

class MyContainer
  extend F::Container::DSL

  namespace :hello do
      f(:world) { -> { "Hello, world!" } }
  end
end

MyContainer['hello.world'].() #=> "Hello, world!"


class Service
  include MyContainer.import(:hello)

  def call
    f(:word)
  end
end

I was thinking about making fun_ruby fully compatible with the Rails environment and its autoloading features based on zeitwerk and the only way do that smoothly is to allow creating containers as constants