sillyforum/app/controllers/forum_topics_controller.rb

class ForumTopicsController < ApplicationController

def index 

      @threads = ForumThread.all
end

 def show
      
  @category = Category.find(params[:category_id])
  #@forum_topics = ForumTopic.all
  #@forum_thread = @category&.forum_topics&.forum_thread(params[:forum_thread_id])
   @forum_topic = @category.forum_topics.find(params[:id])

    @forum_threads = @forum_topic.forum_threads
end

end
private
def params
    params.require(:forum_topic, :title).permit( :description)
end