Rails Haml checkbox
<% for role in Role.find(:all) %>
<div>
  <%= check_box_tag "user[role_ids][]", role.id, @user.roles.include?(role) %>
  <%= role.name %>
</div>

- for role in Role.find(:all)
  %div
    = check_box_tag "user[role_ids][]", role.id, @user.roles.include?(role)
    = role.name