allow to resubmit form via shared link

app/controllers/start_form_controller.rb

@@ -13,8 +13,12 @@ class StartFormController < ApplicationController
   end
 
   def update
+    @submitter = Submitter.new(email: submitter_params[:email])
+
+    if params[:resubmit].blank?
       @submitter = Submitter.where(submission: @template.submissions.where(deleted_at: nil))
-                          .find_or_initialize_by(email: submitter_params[:email])
+                            .find_by(email: submitter_params[:email]) || @submitter
+    end
 
     if @submitter.completed_at?
       redirect_to start_form_completed_path(@template.slug, email: submitter_params[:email])

app/views/icons/_reload.html.erb

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" class="<%= local_assigns[:class] %>" width="44" height="44" viewBox="0 0 24 24" stroke-width="2" fill="none" stroke="currentColor" stroke-linecap="round" stroke-linejoin="round">
+  <path stroke="none" d="M0 0h24v24H0z" fill="none"></path>
+  <path d="M19.933 13.041a8 8 0 1 1 -9.925 -8.788c3.899 -1 7.935 1.007 9.425 4.747"></path>
+  <path d="M20 4v5h-5"></path>
+</svg>

app/views/start_form/completed.html.erb

@@ -24,6 +24,9 @@
         <%= button_to button_title(title: 'Send copy to Email', disabled_with: 'Sending', icon: svg_icon('mail_forward', class: 'w-6 h-6')), send_submission_email_index_path, params: { submitter_slug: @submitter.slug }, form: { onsubmit: 'event.submitter.disabled = true' }, class: 'base-button w-full' %>
       </div>
     <% end %>
+    <div>
+      <%= button_to button_title(title: 'Resubmit', disabled_with: 'Resubmit', icon: svg_icon('reload', class: 'w-6 h-6')), start_form_path(@template.slug), params: { submitter: { email: params[:email] }, resubmit: true }, method: :put, form: { onsubmit: 'event.submitter.disabled = true' }, class: 'white-button w-full' %>
+    </div>
   </div>
 </div>
 <%= render 'shared/attribution', link_path: '/start' %>