gistfile1.rb

class Category < ActiveRecord::Base
  has_many :tickets
  has_many :tasks, :dependent => :destroy
  accepts_nested_attributes_for :tasks, :reject_if => lambda { |a| a[:name].blank? }, :allow_destroy => true  
  
  acts_as_tree
  has_friendly_id :name, :use_slug => true
    
  scope :parent, where({:parent_id => nil}, {})
  scope :children, where({'parent_id > ?', 0}, {})
end

class Tasks < ActiveRecord::Base
  belongs_to :category
  belongs_to :ticket
end