gistfile1.rb

class Ability
   include CanCan::Ability
  def initialize user, options = {}
    
    if !user
    	can :read, :all
   		end
   
	if user.has_role? :admin
   		can :manage, :all
   		end
    
	if user.has_role? :free
    	can :manage, Measurement do |measurement|  
        measurement.try(:user) == user
    		end #do
    		
    	can :create, Measurement
    	
    	
    	
    	end #if

  end #def
end #class