Add mail votes stub to poll stats

So far we don't know about implemenation details.

app/models/poll/stats.rb

@@ -2,22 +2,26 @@ class Poll::Stats
   include Statisticable
   alias_method :poll, :resource
 
+  CHANNELS = %i[web booth mail]
+
   def self.stats_methods
     super +
       %i[total_valid_votes total_white_votes total_null_votes
          total_participants_web total_web_valid total_web_white total_web_null
          total_participants_booth total_booth_valid total_booth_white total_booth_null
+         total_participants_mail total_mail_valid total_mail_white total_mail_null
          total_participants_web_percentage total_participants_booth_percentage
-         valid_percentage_web valid_percentage_booth total_valid_percentage
-         white_percentage_web white_percentage_booth total_white_percentage
-         null_percentage_web null_percentage_booth total_null_percentage]
+         total_participants_mail_percentage
+         valid_percentage_web valid_percentage_booth valid_percentage_mail total_valid_percentage
+         white_percentage_web white_percentage_booth white_percentage_mail total_white_percentage
+         null_percentage_web null_percentage_booth null_percentage_mail total_null_percentage]
   end
 
   def total_participants
     total_participants_web + total_participants_booth
   end
 
-  %i[web booth].each do |channel|
+  CHANNELS.each do |channel|
     define_method :"total_participants_#{channel}" do
       send(:"total_#{channel}_valid") +
         send(:"total_#{channel}_white") +
@@ -53,8 +57,20 @@ class Poll::Stats
     recounts.sum(:null_amount)
   end
 
+  def total_mail_valid
+    0 # TODO
+  end
+
+  def total_mail_white
+    0 # TODO
+  end
+
+  def total_mail_null
+    0 # TODO
+  end
+
   %i[valid white null].each do |type|
-    %i[web booth].each do |channel|
+    CHANNELS.each do |channel|
       define_method :"#{type}_percentage_#{channel}" do
         calculate_percentage(send(:"total_#{channel}_#{type}"), send(:"total_#{type}_votes"))
       end

app/views/polls/stats.html.erb

@@ -30,51 +30,53 @@
             <thead>
               <tr>
                 <th scope="col"><%= t("polls.show.stats.votes") %></th>
-                <th scope="col"><%= t("polls.show.stats.web") %></th>
-                <th scope="col"><%= t("polls.show.stats.booth") %></th>
+                <% Poll::Stats::CHANNELS.each do |channel| %>
+                  <th scope="col"><%= t("polls.show.stats.#{channel}") %></th>
+                <% end %>
                 <th scope="col"><%= t("polls.show.stats.total") %></th>
               </tr>
             </thead>
             <tbody>
               <tr>
                 <th scope="row"><%= t("polls.show.stats.valid") %></th>
-                <td>
-                  <%= @stats[:total_web_valid] %>
-                  <small><em>(<%= @stats[:valid_percentage_web].round(2) %>%)</em></small>
-                </td>
-                <td>
-                  <%= @stats[:total_booth_valid] %>
-                  <small><em>(<%= @stats[:valid_percentage_booth].round(2) %>%)</em></small>
-                </td>
+
+                <% Poll::Stats::CHANNELS.each do |channel| %>
+                  <td>
+                    <%= @stats[:"total_#{channel}_valid"] %>
+                    <small><em>(<%= @stats[:"valid_percentage_#{channel}"].round(2) %>%)</em></small>
+                  </td>
+                <% end %>
+
                 <td>
                   <%= @stats[:total_valid_votes] %>
                   <small><em>(<%= @stats[:total_valid_percentage].round(2) %>%)</em></small>
                 </td>
+
               </tr>
               <tr>
                 <th scope="row"><%= t("polls.show.stats.white") %></th>
-                <td>
-                  <%= @stats[:total_web_white] %>
-                  <small><em>(<%= @stats[:white_percentage_web].round(2) %>%)</em></small>
-                </td>
-                <td>
-                  <%= @stats[:total_booth_white] %>
-                  <small><em>(<%= @stats[:white_percentage_booth].round(2) %>%)</em></small>
-                </td>
+
+                <% Poll::Stats::CHANNELS.each do |channel| %>
+                  <td>
+                    <%= @stats[:"total_#{channel}_white"] %>
+                    <small><em>(<%= @stats[:"white_percentage_#{channel}"].round(2) %>%)</em></small>
+                  </td>
+                <% end %>
+
                 <td><%= @stats[:total_white_votes] %>
                   <small><em>(<%= @stats[:total_white_percentage].round(2) %>%)</em></small>
                 </td>
               </tr>
               <tr>
                 <th scope="row"><%= t("polls.show.stats.null_votes") %></th>
-                <td>
-                  <%= @stats[:total_web_null] %>
-                  <small><em>(<%= @stats[:null_percentage_web].round(2) %>%)</em></small>
-                </td>
-                <td>
-                  <%= @stats[:total_booth_null] %>
-                  <small><em>(<%= @stats[:null_percentage_booth].round(2) %>%)</em></small>
-                </td>
+
+                <% Poll::Stats::CHANNELS.each do |channel| %>
+                  <td>
+                    <%= @stats[:"total_#{channel}_null"] %>
+                    <small><em>(<%= @stats[:"null_percentage_#{channel}"].round(2) %>%)</em></small>
+                  </td>
+                <% end %>
+
                 <td>
                   <%= @stats[:total_null_votes] %>
                   <small><em>(<%= @stats[:total_null_percentage].round(2) %>%)</em></small>
@@ -82,14 +84,14 @@
               </tr>
               <tr>
                 <th scope="row"><%= t("polls.show.stats.total") %></th>
-                <td>
-                  <%= @stats[:total_participants_web] %>
-                  <small><em>(<%= @stats[:total_participants_web_percentage].round(2) %>%)</em></small>
-                </td>
-                <td>
-                  <%= @stats[:total_participants_booth] %>
-                  <small><em>(<%= @stats[:total_participants_booth_percentage].round(2) %>%)</em></small>
-                </td>
+
+                <% Poll::Stats::CHANNELS.each do |channel| %>
+                  <td>
+                    <%= @stats[:"total_participants_#{channel}"] %>
+                    <small><em>(<%= @stats[:"total_participants_#{channel}_percentage"].round(2) %>%)</em></small>
+                  </td>
+                <% end %>
+
                 <td><%= @stats[:total_participants] %></td>
               </tr>
             </tbody>