title: Rails 5.1.2 ransack includes how to add deep associoations?
body: <p>I have following models and i wish search Order model with criteria related to  models Department Supplier </p>
  
  <p>Question is  how to includes other models  Supplier and Department in this code</p>
  
  <pre><code>@q = Order.ransack(params[:q])
  @objednavky = @q.result.includes(:user,:food).page(params[:page])
  </code></pre>
  
  <p>Definitions of models</p>
  
  <pre><code>class Supplier &lt; ApplicationRecord
    has_many :food
  end
  
  class User &lt; ApplicationRecord
    belongs_to :department
    has_many :orders
  end
  
  class Department &lt; ApplicationRecord
    has_many :users
  end
  
  class Food &lt; ApplicationRecord
    belongs_to :supplier
    has_many :order 
  end
  
  class Order &lt; ApplicationRecord
    belongs_to :user
    belongs_to :food
  end
  </code></pre>