How to use scope with acts_as_list

i am working on a task management system for the company i work for. i
just got the rails cookbook and am trying to use the section on creating
a drag and drop sortable list.

the tricky part is that my Task model references the User model in two
different spots. i have one field for the creator of the task and
another for the assignee. so in my Task model i have the following code:

class Task < ActiveRecord::Base
belongs_to :assignee,
:class_name => ‘User’,
:foreign_key => ‘assignee_id’

belongs_to :creator,
:class_name => ‘User’,
:foreign_key => ‘creator_id’

has_many :comments, :dependent => destroy

validates_presence_of :title, :description, :date_due

acts_as_list :scope => :assignee
end

and this is what i have in my User model:

class User < ActiveRecord::Base
has_many :assigned,
:class_name => ‘Task’,
:foreign_key => ‘assignee_id’

has_many :created,
:class_name => ‘Task’,
:foreign_key => ‘creator_id’

has_many :comments, :dependent => destroy

validates_uniqueness_of :username

validates_presence_of :username, :password, :full_name, :email
end

everything works like it’s supposed to until i added the acts_as_list at
the bottom of the Task model. for the scope, i’m not sure what i should
put. when i create a new task, the position is always nil. i’m not sure
if i can use it the way i am trying to or if there is something else i
have to put when my database field names are different than the expected
conventions.

if anyone has any input, i would greatly appreciate it.
thanks

If someone could just tell me what scopte refers to, maybe I can figure
it out on my own. I’m not sure if I use the class, the mysql field, or
the name I gave it in the model.

If someone could just tell me what scope refers to, maybe I can figure
it out on my own. I’m not sure if I use the class, the mysql field, or
the name I gave it in the model.