轨道4中可能存在STI和多态协会吗？不适合我

Question

我有点像ruby on rails的新手，并从samurails.com single table inheritance with rails 4 tutorial开始添加不同的评论类型。这很有效，但我遇到的问题是当我尝试使用多态关联来获取注释和特定类型以在其他模型（如项目和挑战）下运行时。常规评论有效，但具体类型不适用。

我没有看到任何明确说明如何进行此项工作或其他任何选择，所以任何帮助将不胜感激。

class Comment < ActiveRecord::Base

  has_merit
  acts_as_votable

  belongs_to :commentable, :polymorphic => true
  belongs_to :user 
  belongs_to :commenttype
  belongs_to :project

  def self.types
    %w(Question Idea Problem)
  end

  def commentable_type=(sType)
    super(sType.to_s.classify.constantize.base_class.to_s)
  end

  scope :questions, -> {where(type: 'Question')}
  scope :ideas, -> {where(type: 'Idea')}
  scope :problems, -> {where(type: 'Problem')}
end

class Question < Comment

end

class Idea < Comment

end

class Problem < Comment

end

class Project < ActiveRecord::Base

  belongs_to :user

  has_many :comments, :as => :commentable, :class_name => "Comment"
  has_many :questions, :as => :commentable, :class_name => "Question"
  has_many :ideas, :as => :commentable, :class_name => "Idea"
  has_many :problems, :as => :commentable, :class_name => "Problem"

  delegate :questions, :ideas, :problems, to: :comments

end

class CommentsController < ApplicationController
  before_action :set_commentable, only: [:index, :new, :create]
  before_action :set_type
  before_action :set_comment, only: [:show, :edit, :update, :destroy]

  def index
    @comments = type_class.all
  end

  def show
  end

  def new
    @comment = type_class.new
  end

  def edit
  end

  def create 
      @comment = @commentable.comments.new(comment_params)
      @comment.user = current_user
      if @comment.save
        redirect_to :back, notice: "#{type} was successfully added."
      else
        render action: 'new'
      end
  end

  def update
    if @comment.update(comment_params)
      redirect_to @comment.commentable, notice: "#{type} was successfully updated."
    else
      render action: 'edit'
    end
  end

  def destroy
    @user = current_user
    @comment = @commentable.comments.where(comment_user: current_user).first
    @commentable.comment.destroy
    respond_to do |format|
      format.html { redirect_to @commentable, notice: "Comment was deleted." }
      format.js
  end
end

private

def set_comment
  @comment = type_class.find(params[:id])
end

def set_type
  @type = type
end

def type
  Comment.types.include?(params[:type]) ? params[:type] : "Comment"
end

def type_class
  type.constantize
end

def set_commentable
  @commentable = find_commentable
end

# add more commentable models here
def find_commentable
  if params[:challenge_id]
    Challenge.find(params[:challenge_id])
  else
  end
end

def find_commentable
  if params[:project_id]
    Project.find(params[:project_id])
  else
  end
end


  def comment_params 
    params.require(type.underscore.to_sym).permit(:body, :type, :user_id, :commentable_id, :commentable_type, :commentable, :comment_type) 
  end

end

module CommentsHelper

  def sti_comment_path(type = "comment", comment = nil, action = nil)
    send "#{format_sti(action, type, comment)}_path", comment
  end

  def format_sti(action, type, comment)
    action || comment ? "#{format_action(action)}#{type.underscore}" : "#{type.underscore.pluralize}"
  end

  def format_action(action)
    action ? "#{action}_" : ""
  end

end

<%= form_for [commentable, Comment.new], :html => { :multipart => true } do |f| %>

<%= f.text_area :body, class: "form-control", placeholder: "What's on your mind?" %>

<%= f.label :type %><br>
<%= f.select :type, Comment.types.map {|r| [r.humanize, r.camelcase]}, {}, disabled: @type != "Comment" %> 

    <%= f.submit "Post", class: "btn pull-right" %>