List single_resource_admin resources in the UI (#11049)

* List single_resource_admin resources in the UI

* Add a comment to explain Role#resource_name

app/models/role.rb

@@ -32,4 +32,13 @@ class Role < ApplicationRecord
             inclusion: { in: ROLES }
 
   scopify
+
+  # Returns a somewhat friendly name for the resource related to a given role.
+  # In the case of Tag Moderators, a resource_type is not present, so we use the
+  # resource_id to grab the specific Tag related to that moderator's role.
+  def resource_name
+    return resource_type unless resource_id
+
+    Tag.find(resource_id).name
+  end
 end

app/views/admin/users/_activity.html.erb

@@ -15,7 +15,7 @@
     <p>(view full history in notes below)</p>
     <ul>
       <% @user.roles.each do |role| %>
-        <li><%= role.name %> <em><%= "- #{Tag.find(role.resource_id).name}" if role.resource_id.present? %></em></li>
+        <li><%= role.name %> <em><%= role.resource_name.to_s %></em></li>
       <% end %>
     </ul>
   </div>