何とも言えない設計

app__commands__follow_command.rb

class FollowCommand
  def initialize(user, params)
    @user = user
    @params = params
  end

  using UserCommand::Follow
  def execute!
    user = User.find(@params[:id])
    User.transaction do
      @user.follow!(user)
    end
  end
end

app__controller__followees_controller.rb

class FolloweesController < ApplicationController
  using UserRepository::Follow

  def create
    following_user = User.find(params[:id])
    current_user.follow!(following_user)
    # using UserRepository::Follow {
    #   current_user.follow!(following_user) 
    # }
  end
end

app__repository__user_command.rb

module UserRepository
  module Follow
    refine User do
      def follow!(another_user)
        relationship.create!(user: self, following: another_user)
      end
    end
  end
end