Display tag counts in the filter menu

- Provides a little information scent
- Prevents being surprised by "no results"

app/models/tag.rb

@@ -13,4 +13,8 @@ class Tag < ApplicationRecord
   def hashtag
     "#" + title
   end
+
+  def cards_count
+    cards.count
+  end
 end

app/views/events/filter/_tag.html.erb

@@ -1,7 +1,7 @@
 <li class="popup__group flex align-center" data-filter-target="item" data-navigable-list-target="item">
   <%= icon_tag "tag" %>
   <%= link_to cards_path(tag_ids: [ tag ]), class: "btn popup__item min-width flex-item-grow" do %>
-    <span class="overflow-ellipsis"><%= tag.title %></span>
+    <span class="overflow-ellipsis"><%= tag.title %> (<%= tag.cards_count %>)</span>
     <span class="translucent flex-item-no-shrink flex-item-justify-end"> ›</span>
   <% end %>
 </li>