Merge branch 'feature/precalculate-authorized-projects' into 'master'

Precalculate authorized projects in database

## What does this MR do?
It caches user's authorized projects in database instead of using multiple unions, which should simplify and speed-up things since this operation (getting authorized projects) is used a lot.

## Are there points in the code the reviewer needs to double check?
Did we miss a scenario where we need to refresh the list of projects?

## 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
  - [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)

## What are the relevant issue numbers?
#23150 

See merge request !6839

2 files changed, 24 insertions, 0 deletions

diff --git a/db/migrate/20161010142410_create_project_authorizations.rb b/db/migrate/20161010142410_create_project_authorizations.rb
new file mode 100644
index 00000000000..e095ab969f8
--- /dev/null
+++ b/db/migrate/20161010142410_create_project_authorizations.rb
@@ -0,0 +1,15 @@
+class CreateProjectAuthorizations < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    create_table :project_authorizations do |t|
+      t.references :user, foreign_key: { on_delete: :cascade }
+      t.references :project, foreign_key: { on_delete: :cascade }
+      t.integer :access_level
+
+      t.index [:user_id, :project_id, :access_level], unique: true, name: 'index_project_authorizations_on_user_id_project_id_access_level'
+    end
+  end
+end
diff --git a/db/migrate/20161017091941_add_authorized_projects_populated_to_users.rb b/db/migrate/20161017091941_add_authorized_projects_populated_to_users.rb
new file mode 100644
index 00000000000..8f6be9dd677
--- /dev/null
+++ b/db/migrate/20161017091941_add_authorized_projects_populated_to_users.rb
@@ -0,0 +1,9 @@
+class AddAuthorizedProjectsPopulatedToUsers < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    add_column :users, :authorized_projects_populated, :boolean
+  end
+end