add priority to notification table

test plan
 - db migration should run

fixes: KNO-362
flag=none

Change-Id: I8a09c9deff8dfa904ba06ab703a2f84bfa16972e
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/231072
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
QA-Review: Cody Cutrer <cody@instructure.com>
Product-Review: Cody Cutrer <cody@instructure.com>

db/migrate/20200323201142_add_priority_to_notification.rb

@@ -0,0 +1,23 @@
+class AddPriorityToNotification < ActiveRecord::Migration[5.2]
+  tag :predeploy
+
+  PRIORITY_MESSAGE_LIST = ["Account User Registration",
+                           "Confirm Email Communication Channel",
+                           "Confirm Registration",
+                           "Confirm SMS Communication Channel",
+                           "Enrollment Invitation",
+                           "Enrollment Notification",
+                           "Forgot Password",
+                           "Manually Created Access Token Created",
+                           "Merge Email Communication Channel",
+                           "Pseudonym Registration",
+                           "Pseudonym Registration Done",
+                           "Self Enrollment Registration"].freeze
+
+  # Generally we don't want to add a default to a new column, but we know this
+  # is a very small table and it is ok
+  def change
+    add_column :notifications, :priority, :boolean, default: false, null: false
+    Notification.where(name: PRIORITY_MESSAGE_LIST).update_all(priority: true) if Shard.current.default?
+  end
+end