Fix few bugs related to recent notifications refactoring

app/controllers/profiles/notifications_controller.rb

 class Profiles::NotificationsController < Profiles::ApplicationController
   def show
     @user = current_user
-    @notification = current_user.notification
     @group_notifications = current_user.notification_settings.for_groups
     @project_notifications = current_user.notification_settings.for_projects
   end

app/models/member.rb

@@ -163,7 +163,7 @@ class Member < ActiveRecord::Base
   end
 
   def create_notification_setting
-    user.notification_setting.find_or_create_for(source)
+    user.notification_settings.find_or_create_for(source)
   end
 
   def notification_setting