app/views/user/edit_profile.html.erb
<% content_for :title, " - Edycja profilu" %>
<h3>Edycja profilu użytkownika</h3>
<%= simple_form_for @user,
url: url_for(action: 'edit_profile', controller: 'user'),
method: :post do |f| %>
<%= f.input :profile_description, label: 'Opis profilu:', as: :pagedown, input_html: { preview: true, rows: 20 } %>
<%= f.association :school, collection: @schools, label_method: :name, value_method: :id, label: 'Szkoły', input_html: { class: 'selectpicker', 'data-width' => '100%'} -%>
<div class="buttons">
<%= f.button :submit, value: 'Aktualizuj', class: 'btn-primary btn-save' %>
</div>
<% end %>