app/views/expenses/_form.html.erb
<%= simple_form_for(@expense, multipart: true) do |f| %>
<%= f.error_notification %>
<div class="form-inputs">
<%= f.input :name %>
<%= f.input :date, as: :string, input_html: { data: {behaviour: "datepicker"}, value: @expense.date.to_s } %>
<%= f.input :amount %>
<%= f.input :note %>
<%= f.input :file %>
</div>
<div class="form-actions">
<%= f.button :submit %>
</div>
<% end %>