app/views/shared/_edit_mail_template.html.erb
<%= form_for @mail_template do |f| %>
<%= f.label :body, 'Message:' %>
<%= f.text_area :body, :class => "wide_form", :cols => "10", :rows => "10" %><br><br>
<p>
<%= link_to 'Accept invitation', accept_invitation_url(@resource, :invitation_token => @resource.raw_invitation_token) %>
</p><br>
<%= f.label :footnote, 'Footnote:' %>
<%= f.text_area :footnote, :class => "wide_form", :cols => "10", :rows => "8" %><br><br>
<%= f.submit 'Update template', class: 'btn btn-primary' %>
<% end %>