Add mentionees as watchers

app/models/notifier/event.rb

@@ -1,5 +1,6 @@
 class Notifier::Event < Notifier
   delegate :card, :creator, to: :source
+  delegate :watchers_and_subscribers, to: :card
 
   private
     def resource
@@ -15,9 +16,22 @@ class Notifier::Event < Notifier
         when "assigned"
           source.assignees.excluding(card.collection.access_only_users)
         when "published"
-          card.watchers_and_subscribers(include_only_watching: true).without(creator)
+          watchers_and_subscribers(include_only_watching: true).without(creator, *mentionees)
+        when "commented"
+          watchers_and_subscribers.without(creator, *mentionees)
         else
-          card.watchers_and_subscribers.without(creator)
+          watchers_and_subscribers.without(creator)
+      end
+    end
+
+    def mentionees
+      case source.action
+        when "published"
+          source.card.mentionees
+        when "commented"
+          source.comment.mentionees
+        else
+          []
       end
     end
 end