app/views/schools/school_group/_form.html.erb
<h1>School group: <%= school.name %> </h1>
<%= form_tag school_school_group_path(school), method: method do %>
<h2>School group</h2>
<p>School groups are used to collect associated schools together, usually by area.</p>
<div class="form-group">
<%= label_tag :school_group_id, 'Group' %>
<%= select_tag :school_group_id, options_from_collection_for_select(@school_groups, 'id', 'name', @school.school_group_id), include_blank: true, class: 'form-control' %>
</div>
<div class="actions">
<%= submit_tag submit_text, class: 'btn btn-primary' %>
</div>
<% end %>