Merge branch '19693-emoji-awards-aren-t-deleted-for-deleted-users' into 'master'

Delete award emoji when deleting a user

## What does this MR do?

Fix the problem where a user's award emoji aren't deleted when the user is deleted.

## Are there points in the code the reviewer needs to double check?

The corresponding SELECT for the migration runs in 0.3s on staging, but I can't test the delete there or on production easily. It should be reasonably quick.

## Why was this MR needed?

There was a typo in an association 😱 

## What are the relevant issue numbers?

Closes #19693.

## Screenshots (if relevant)

Nope.

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~API support added~~
- Tests
  - ~~Added for this feature/bug~~
  - [ ] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5216

CHANGELOG

@@ -8,6 +8,7 @@ v 8.10.0 (unreleased)
   - Refactor repository paths handling to allow multiple git mount points
   - Optimize system note visibility checking by memoizing the visible reference count !5070
   - Add Application Setting to configure default Repository Path for new projects
+  - Delete award emoji when deleting a user
   - Remove pinTo from Flash and make inline flash messages look nicer !4854 (winniehell)
   - Wrap code blocks on Activies and Todos page. !4783 (winniehell)
   - Align flash messages with left side of page content !4959 (winniehell)

app/models/user.rb

@@ -87,7 +87,7 @@ class User < ActiveRecord::Base
   has_many :builds,                   dependent: :nullify, class_name: 'Ci::Build'
   has_many :todos,                    dependent: :destroy
   has_many :notification_settings,    dependent: :destroy
-  has_many :award_emoji,              as: :awardable, dependent: :destroy
+  has_many :award_emoji,              dependent: :destroy
 
   #
   # Validations

db/migrate/20160712171823_remove_award_emojis_with_no_user.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveAwardEmojisWithNoUser < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  # When using the methods "add_concurrent_index" or "add_column_with_default"
+  # you must disable the use of transactions as these methods can not run in an
+  # existing transaction. When using "add_concurrent_index" make sure that this
+  # method is the _only_ method called in the migration, any other changes
+  # should go in a separate migration. This ensures that upon failure _only_ the
+  # index creation fails and can be retried or reverted easily.
+  #
+  # To disable transactions uncomment the following line and remove these
+  # comments:
+  # disable_ddl_transaction!
+
+  def up
+    AwardEmoji.joins('LEFT JOIN users ON users.id = user_id').where('users.id IS NULL').destroy_all
+  end
+end

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: 20160707104333) do
+ActiveRecord::Schema.define(version: 20160712171823) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"