What's a simpler way of doing this form collection?

This code works, but I think the solution is ugly, please advise.

User updates a standard form_for, the form is re-rendered with
checkboxes next to each updated line. The user is expected to select
up to 3 checkboxes which will be saved in the user model under columns
(top_1of3, top_2of3, top_3of3).


<% form_tag :action => ‘top_three’ do %>
<% for line in @updated_info do %>
<%= check_box_tag( “choice_” + @updated_info.index(line).to_s ,
line ) %><%= line %>

<% end %>
<%= submit_tag %>
<% end %>


choices = {}

for i in 0..50
  choice = "choice_" + i.to_s
  choice = choice.intern

  if !params[choice].nil? and choices["top_1of3"].nil?
    choices["top_1of3"] = params[choice]

  elsif !params[choice].nil? and choices["top_2of3"].nil?
    choices["top_2of3"] = params[choice]

  elsif !params[choice].nil? and choices["top_3of3"].nil?
    choices["top_3of3"] = params[choice]


if @user.update_attributes(choices)