application URL

Hi all. I'm trying to get gravtastic working at my comments model, so I'm
doing this:

class Comment < ActiveRecord::Base
  validates_presence_of :commentary

  belongs_to :commentary, :polymorphic => true

  attr_accessor :anon
  
  is_gravtastic :rating => 'R',
                 :size => 40 ,
           :default => "/images/no_gravatar.png"
end

  My doubt is: using comment.gravatar_url gives me the following:

http://gravatar.com/avatar/HASH.png?d=%2Fimages%2Fno_gravatar.png&r=R&s=40

  And it doesn't renders my image correctly. How can I get my full application
URL as http://my.domain.tld/app/images/no_gravatar.png ?

  Thanks,

  Hi all. I'm trying to get gravtastic working at my comments model, so I'm
doing this:

class Comment < ActiveRecord::Base
  validates_presence_of :commentary

  belongs_to :commentary, :polymorphic => true

  attr_accessor :anon

  is_gravtastic :rating => 'R',
                 :size => 40 ,
           :default => "/images/no_gravatar.png"
end

  My doubt is: using comment.gravatar_url gives me the following:

http://gravatar.com/avatar/HASH.png?d=%2Fimages%2Fno_gravatar.png&r=R&a

mp;s=40

  And it doesn't renders my image correctly. How can I get my full
application URL as http://my.domain.tld/app/images/no_gravatar.png ?

  I'm using Mongrel as development server, but I'll deploy it to Apache +
Passenger.

  I'm trying to use request_uri, but no success.

  Any kind of tips, please?

  Best regards,