Merge branch 'issue_22269' into 'master'

Mattermost Notifications Service

## What does this MR do?
closes #22269 

## Screenshots 

![mattermost](/uploads/de71c121f544a91305b6dfa6dc4c5738/mattermost.png)  
![slack](/uploads/081d75d49239319d94332abda214fb98/slack.png)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)


See merge request !7764

3 files changed, 20 insertions, 2 deletions

diff --git a/db/migrate/20141006143943_move_slack_service_to_webhook.rb b/db/migrate/20141006143943_move_slack_service_to_webhook.rb
index 8cb120f7007..42e88d6d6e3 100644
--- a/db/migrate/20141006143943_move_slack_service_to_webhook.rb
+++ b/db/migrate/20141006143943_move_slack_service_to_webhook.rb
@@ -1,7 +1,11 @@
 # rubocop:disable all
 class MoveSlackServiceToWebhook < ActiveRecord::Migration
+
+  DOWNTIME = true
+  DOWNTIME_REASON = 'Move old fields "token" and "subdomain" to one single field "webhook"'
+
   def change
-    SlackService.all.each do |slack_service|
+    SlackNotificationService.all.each do |slack_service|
       if ["token", "subdomain"].all? { |property| slack_service.properties.key? property }
         token = slack_service.properties['token']
         subdomain = slack_service.properties['subdomain']
diff --git a/db/migrate/20161213172958_change_slack_service_to_slack_notification_service.rb b/db/migrate/20161213172958_change_slack_service_to_slack_notification_service.rb
new file mode 100644
index 00000000000..a7278d7b5a6
--- /dev/null
+++ b/db/migrate/20161213172958_change_slack_service_to_slack_notification_service.rb
@@ -0,0 +1,14 @@
+class ChangeSlackServiceToSlackNotificationService < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = true
+  DOWNTIME_REASON = 'Rename SlackService to SlackNotificationService'
+
+  def up
+    execute("UPDATE services SET type = 'SlackNotificationService' WHERE type = 'SlackService'")
+  end
+
+  def down
+    execute("UPDATE services SET type = 'SlackService' WHERE type = 'SlackNotificationService'")
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 67ff83d96d9..3786a41f9a9 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20161212142807) do
+ActiveRecord::Schema.define(version: 20161213172958) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"