openproject/app/views/users/_groups.html.erb

<%#-- copyright
OpenProject is a project management system.
Copyright (C) 2012-2017 the OpenProject Foundation (OPF)

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License version 3.

OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
Copyright (C) 2006-2017 Jean-Philippe Lang
Copyright (C) 2010-2013 the ChiliProject Team

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

See doc/COPYRIGHT.rdoc for more details.

++#%>
<%= labelled_tabular_form_for(:user, url: { action: 'update' }, html: {method: :put}) do %>
  <section class="form--section">
    <% Group.all.sort.each do |group| %>
      <label class="form--label-with-check-box">
        <%= styled_check_box_tag 'user[group_ids][]', group.id, @user.groups.include?(group) %>
        <%= group %>
      </label>
    <% end %>
    <%= hidden_field_tag 'user[group_ids][]', '' %>
  </section>
  <%= styled_button_tag l(:button_save), class: '-highlight -with-icon icon-checkmark' %>
<% end %>