app/views/shared/partials/_organizer_form.html.erb
<%= form.fields_for :organizer, record.organizer do |fo| %>
<div class="row">
<div class="col">
<div class="form-group">
<label for="description">
Institution/Firma * <small>(Pflichfeld, wenn hier weitere Angaben gemacht werden)</small>
</label>
<%= fo.text_field :name, class: "form-control" %>
</div>
</div>
</div>
<%= fo.fields_for :contact, record.try(:organizer).try(:contact) || OpenStruct.new(web_urls: [OpenStruct.new]) do |fc| %>
<%= render partial: "shared/partials/contact_form", locals: { form: fc, contact: fc.object } %>
<% end %>
<%= fo.fields_for :address, record.try(:organizer).try(:address) || OpenStruct.new(geo_location: nil) do |fa| %>
<%= render partial: "shared/partials/address_form", locals: { form: fa, address: fa.object } %>
<% end %>
<% end %>