This can be used to resolve N+1 query problems. Bullet is disabled by
default and can be enabled by starting Rails with the environment
variable ENABLE_BULLET set to a non empty value (e.g. "true").

Change "+" icon under "Files" section to have three options:

* Create file
* Upload file
* New directory

Upload file is no longer accessible from the "Create file" page.
Users can now select a target branch in upload file as well.

Closes #2799: Fixes a bug where file modes were overwritten after a commit

Closes https://github.com/gitlabhq/gitlabhq/issues/8253: Existing files
can no longer be overwritten in the "Create file" section.

Closes #2557

This allows me to use this Gem for benchmarking without having to
add/remove it every time.

This allows us to see a breakdown of API requests in New Relic.

Also update Kaminari gem to the latest version

Addresses internal https://dev.gitlab.org/gitlab/gitlabhq/issues/2605

See https://github.com/tinfoil/devise-two-factor/pull/43

- Change Notify to Ci::Notify
- Downgrade sidekiq to fix CE errors: otherwise we need to check deliverables

This allows us to properly handle authentication errors.

Closes #2128

Closes #2433