account admins can create "Alerts" from the account
settings page that show up as sticky messages on the
user dashboards. The alerts stay until the end_at
date, or until the user clicks the "close" link. If
you add an alert to the site_admin account then it's
considered a global alert and will go to all root
accounts.
fixes#3738
Change-Id: I47e6eaf717145af24d847d4387e0ad5c36800094
Reviewed-on: https://gerrit.instructure.com/2293
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Zach Wily <zach@instructure.com>
Brian Whitmer