destroy notifications when marked as read

app/controllers/notifications_controller.rb

@@ -1,9 +1,26 @@
 class NotificationsController < ApplicationController
   before_action :authenticate_user!
-  load_and_authorize_resource class: "User"
+  after_action :mark_as_read, only: :show
+  skip_authorization_check
 
   def index
-    @notifications = current_user.notifications.recent.for_render
+    @notifications = current_user.notifications.unread.recent.for_render
   end
 
+  def show
+    @notification = current_user.notifications.find(params[:id])
+    redirect_to url_for(@notification.notifiable.commentable)
+  end
+
+  def mark_all_as_read
+    current_user.notifications.each { |notification| notification.mark_as_read }
+    redirect_to notifications_path
+  end
+
+  private
+
+    def mark_as_read
+      @notification.mark_as_read
+    end
+
 end