Paperclip order of params

In my website I'm using Paperclip to take care of the attached files.

I have a model "image" who has many "collections".
A "collection" belongs to a "resolution".

I'm displaying the form of an image with a list of available resolutions.

In the model Collection:
has_attached_file :picture,
    :url => "...",
    :path => "...",
    :styles => { :custom => Proc.new { |col| "#{col.resolution.width}x#{col.resolution.height}" }}
   }}

Problem
When an image is updated, the Proc is executed and I have a "nil" exception.
I'm wondering why "resolution" is nil because the params contain a resolution_id.

Solution
In fact, it depends of the order you pass the parameters.

At first, the view was like this :
= f.file_field :picture
= f.hidden_field :resolution_id

But I should do like this:
= f.hidden_field :resolution_id
= f.file_field :picture


The "resolution_id" should be first !
By doing so, Rais is creating the relation between "resolution" and "collection" first, and then he is applying the style.

So, sometimes the order of the params is important!

And that's it!

Edit
Too bad for me, in fact the order is not sure... It is working on my development environment, but not in my production environment...

Rails default_scope delete

I have a model called User with a default_scope where('deleted_at is null'), because I'm using some kind of "soft delete".

Problem:
I want to delete an object who has been soft deleted.

First, I create an object :
user = User.new

Then I soft delete it:
user.soft_delete
# this set deleted_at = Time.now

Then I want to delete it:
user.delete
# nothing happen !
# the query looks like this: delete from users where id = 1 and deleted_at is null

Solution:
I can think about 2 solutions:

1) Is to execute sql code directly:

ActiveRecord::Base.connection.execute("delete from ...");

2) Use "unscoped"

User.unscoped.where(:id => 1).delete_all

And that's it!

If you know a better solution, please let me know