NoMethodError, undefined method in my controller Ruby on Rails -

i'm getting nomethoderror @ /article

undefined method 'article_category' mongoid::criteria

article model

class article   include mongoid::document   include mongoid::timestamps    field :title, type: string   field :content, type: string    belongs_to :user   #kategorie   belongs_to :article_category 

article controler

class articlescontroller < applicationcontroller     def article     @article = article.order_by(created_at: 'desc').page params[:page]   end    def view_article     @article = article.find(params[:id])   end end 

articlecategory model

class articlecategory   include mongoid::document   include mongoid::timestamps     field :name, type: string    has_many :articles   end 

article_category controller

class articlecategoriescontroller < applicationcontroller   def category # give view categories list   @categories = articlecategory.order("created_at desc")  end   def show    @category = articlecategory.find(params[:id])  end  end 

routes

  'article', to: 'articles#article'   'article/:id', to: 'articles#view_article', as: 'view_article'   resources :article_categories   resources :articles, shallow: true end 

is there category controller ?

in article view i'm displaying in way.

<%= link_to @article.article_category.name, @article.article_category -%> 

your problem in articlescontroller#article:

def article   @article = article.order_by(created_at: 'desc').page params[:page] end 

that sequence of order_by , page calls building query have mongoid::criteria in @article rather single article instance template apparently expects.

i'm not sure presence of view_article , article/:id route suggests article method should like:

def article   @articles = article.order_by(created_at: 'desc').page params[:page]   # ------^ end 

and corresponding view should iterate on @articles display each article.