Separating domain logic: emails?

gistfile1.rb

# I'm trying to follow advice from "Keynote: Architecture the Lost Years by Robert Martin"
# ( https://www.youtube.com/watch?v=WpkDN78P884 )
#
# I created a separate gem for my domain logic. It has entities and interactors.
#
# An example of a rails controller:
class CommentsController < ApplicationController
  include MyApp::Interactors

  def create
    # current_user is passed to every interactor so that we can check permissions.
    post = FindsPosts.new(current_user).find(params[:id])

    comment_params = params[:comment].slice(:body)
    comment = CreatesComment.new(post, current_user).create(comment_params)

    redirect_to post_path(post.id)
  end
end

# An example of an interactor
class CreatesComment
  def initialize(post, user)
    @post = post
    @user = user
    @post_owner = post.owner
  end

  def create(attributes)
    # Checks if user has permissions to create the post

    # Creates the comment

    # IMPORTANT: Sends email to the post owner. I only pass ids because it is a delayed job.
    EmailQueue.add(@post_owner, :comment_received, @post.id, comment.id)

    # ...
  end
end

# So far so good.
# Now to the actual email sending part (this is in rails app):
class Notifier < ActionMailer::Base
  def comment_received(subject_id, post_id, comment_id)
    # How do I fetch subject (receiver), post and comment?
    #
    # My initial thought was to use interactor, but this is not really an use case.
    # This is already a part of an use case that is just executed later.
    #
    # Second option is to directly fetch it from app using MyApp::Repositories::Post.get(post_id)
    # But I don't think that rails app should know about MyApp structure except for interactors.
    #
    # I also thought that maybe this is application logic and should not be in the rails app. But it
    # renders views, and delivers emails so it sound like a delivery mechanism.
    #
    # UPDATE:
    # Just thought about one idea more: Maybe I should pass a complete data structure to the queue
    # instead of the ids. So that comment_received method takes one parameter and inside it there are
    # primitive attributes: (subject_email, comment_body, etc)
    #
    # Any ideas how to handle this?
  end
end