creating association between tutorials and categories

I have created a tutorials section and categories section. now i want to create association between these two sections.i have added has_many in my tutorials model. this is my tutorial models definition:

class Tutorial < ActiveRecord::Base
    has_many :tutorialcategories

I got an error "undefined method tutorial category" in show method.

this is my tutorialcategories controller's definition

class TutorialcategoriesController < ApplicationController
    respond_to :json

  def show
    @tutorials=Tutorial.order("id ASC").all
    @category = Tutorialcategory.find(params[:id])