app_actors_user.rb

class User
  def initialize(context)
    @context = context
  end

  def profile
    @context.system.collections.profiles.where(id: @context.session[:current_user_id]).first
  end
end

app_contexts_shop_signup.rb

class Shop::SignupContext < ApplicationContext
  def user
    @user ||= User.new(self)
  end

  def system
    @system ||= System.new(self)
  end


  def create
    if user.extend(User::Guest).create_account(params[:profile])
      system.extend(System::Shop)
      ProductsPresenter.new system.products.first(5) # just example, show 5 first products in response
    end
  end
end

app_roles_system_shop.rb

module System::Shop
  def products
    @context.system.collections.products.where(shop_id: @context.session[:shop_id])
  end
end

app_roles_user_guest.rb

module User::Guest
  def create_account(account_attributes)
    # ...
  end
end