Help with associations

Rails
1

Hello all!

I have the following models:

Document belongs to a Task and to a Documentgroup and I want to select
the
Task that Document belongs to using a link where I can select the Task,
but
I also want to allow the user to select the Documentgroup using in the
same
way. How can I maintain the document state between these requests?

Here is the code:

Models:

class Document < ActiveRecord::Base
belongs_to :task
belongs_to :documentgroup
end

class Task < ActiveRecord::Base
end

class Documentgroup < ActiveRecord::Base
end

Views:

edit view:

<%= start_form_tag :action => “update” %>

<%= text_field_tag(“name”, @document.name) %>
<%= text_field_tag(“description”, @document.description) %>

<%= text_field_tag(“task”, @task.name) %>
<%= link_to “Select”, :action => ‘select_task’ %>

<%= text_field_tag(“documentgroup”, @documentgroup.name) %>
<%= link_to “Select”, :action => ‘select_documentgroup’ %>

<%= submit_tag “Change”, { ‘name’ => ‘change’} %>

<%= end_form_tag %>

select_task view:

<% for task in @tasks %>

<% end %>
<%= task.name %> <%= link_to "Select", :action => "edit", :value => task.id %>

select_documentgroup view:

<% for documentgroup in @documentgroups %>

<% end %>
<%= documentgroup.name %> <%= link_to "Select", :action => "edit", :value => documentgroup.id %>