Specify cancan attributes_for conditions even when using block syntax

ability.rb

# A quick hack that shows how to add a hash 
# of conditions to cancan rules when the block syntax is used

# (sadly, you can't use the conditions and the block syntax at the time, so
# when you need to use a block you have to give up the conditions. until now!)

class Ability
  include CanCan::Ability

  def initialize(user)

    # some rules here ...

    can :create, Pizza do |pizza|
      user.recipes.include?("pizza") ||
        user.appliances.include?("microwave")
    end

    rules.last.instance_variable_set("@conditions", { user_id: user.id })

    #...now when PizzaController#new builds a Pizza via load_resource
    #that pizza's user_id will automatically be populated
    #just as if you had written the rule as:
    #  can :create, Pizza, user_id: user.id

    # more rules here...
  end
end

Yay Ruby!!