collection_select problem

hi, i’am novice at ruby on Rails framework. i’am trying to add a plugin for Redmin wich is a Rails application. My problem: i have this code in my html.erb file: <%= form_tag :action => “sauver” >

< @types.each do |untype| > < end %>
<= untype[:alertetype] > <= collection_select(:tracker, :id, @trackers, :id, :name, options ={:prompt => "choisir un tracker"}) >

<%= submit_tag “valider” %>

i need to recover all values selected. When i use “params[:tracker][:id]” i have just one value posted. Could you help me please. Thank you in advance. Cordially

pass the :multiple option for the collection_select

http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/select