def policy(name, options = {}, &block)
      p = Sprinkle::Policy.new(name, options, &block)
      POLICIES << p
      p
    end
def policy(name, options = {}, &block)
      p = Sprinkle::Policy.new(name, options, &block)
      POLICIES << p
      p
    end
Defines a single policy. Currently the only option, which is also
 required, is :roles, which defines which servers a policy is
 used on.