gistfile1.rb

<% form_for Job.new do |f| %>

  #
  # Here, we use a multiple select, but any forrm element named
  # "job_specializations[]" will populate the jobs.specializations
  # array
  #
  <%= f.select :specializations, 
                ["rails", "ruby", "js", "python], 
                :multiple => true %>

<% end %>