Merge branch 'ce-11629-notify-users-when-their-ci-minutes-quota-has-run-out' into 'master'

Backport of gitlab-ee!13735

See merge request gitlab-org/gitlab-ce!29289

db/migrate/20190606014128_add_last_ci_minutes_notification_at_to_namespaces.rb

+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddLastCiMinutesNotificationAtToNamespaces < ActiveRecord::Migration[5.1]
+  DOWNTIME = false
+
+  def change
+    add_column :namespaces, :last_ci_minutes_notification_at, :datetime_with_timezone
+  end
+end

db/schema.rb

@@ -1440,6 +1440,7 @@ ActiveRecord::Schema.define(version: 20190611161641) do
     t.string "runners_token_encrypted"
     t.integer "project_creation_level"
     t.boolean "auto_devops_enabled"
+    t.datetime_with_timezone "last_ci_minutes_notification_at"
     t.index ["created_at"], name: "index_namespaces_on_created_at", using: :btree
     t.index ["name", "parent_id"], name: "index_namespaces_on_name_and_parent_id", unique: true, using: :btree
     t.index ["name"], name: "index_namespaces_on_name_trigram", using: :gin, opclasses: {"name"=>"gin_trgm_ops"}

doc/user/admin_area/settings/continuous_integration.md

@@ -134,6 +134,14 @@ to a different Group.
 be deducted from your Additional Minutes quota immediately after your purchase of additional
 minutes.
 
+## What happens when my CI minutes quota run out
+
+When the CI minutes quota run out, an email is sent automatically to notifies the owner(s) of the group/namespace which
+includes a link to [purchase more minutes](https://customers.gitlab.com/plans).
+
+If you are not the owner of the group, you will need to contact them to let them know they need to
+[purchase more minutes](https://customers.gitlab.com/plans).
+
 ## Archive jobs **[CORE ONLY]**
 
 Archiving jobs is useful for reducing the CI/CD footprint on the system by