* master: (26 commits)
  Remove extra subscribable_type filter on migration
  Add feature spec for labels subscription
  Avoid code duplication for label subscription status on label partial
  Rename LabelSubscription javascript to ProjectLabelSubscription
  Fix label subscription menu on small screens resolution
  Allow users to subscribe to a group label at group or project level
  Use button instead of an icon to subscribe/unsubscribe to labels
  Add CHANGELOG entry
  Add toggle_subscription action to Groups::LabelsController
  Allow subscriptions to be created without a project
  Use subqueries instead of joins to migrate subscriptions
  Add helper method to toggle label subscription on labels controller spec
  Remove default value for `project` argument on subscribable concern
  Use @project as default on ToggleSubscriptionAction concern
  Allow users to subscribe to group labels at project-level
  Pass project to Entities::Label to check if user is subscribed
  Fix specs to pass a project when creating subscriptions
  Refactoring label subscription toggle button text to accept a project
  Refactoring label subscription status to accept a project
  Refactoring notification service to find subscriptions per project
  ...

* master: (154 commits)
  Fix typos
  Fix wrong changelog item
  Add missing item for 8.13.6
  Change last_used_at to use touch
  Add chat_name partial
  Mention Git strategy none
  Fix code review
  adds fix for security issue when annonymous user does not ...
  Remove ToC since it's now supported in the docs portal itself
  Add 8.14 to versions with further additions to review apps
  Add Limitations sections to environments and review apps docs
  Add link to environments docs
  Fix URL to review apps docs
  Add a prerequisites section, add some links
  Link to NGINX example project for the time being
  Get rid most of the irrelevant sections
  Add note about current limitation in $CI_BUILD_REF_NAME
  Add an intro and an Overview section for Review Apps
  WIP review apps
  Add Review apps link to CI README
  ...

Conflicts:
  spec/features/environments_spec.rb

Support subscribing to group labels

https://gitlab.com/gitlab-org/gitlab-ce/issues/23586

See merge request !7215

Allows to authorize chat user against GitLab.

This is needed for: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7438

See merge request !7450

Remove unused CI gems

See merge request !7522

Start to document how to code for CE with EE in mind

Closes #23740

[ci skip]

See merge request !7248

Signed-off-by: Rémy Coutable <remy@rymai.me>

[ci skip]
Signed-off-by: Rémy Coutable <remy@rymai.me>

[ci skip]
Signed-off-by: Rémy Coutable <remy@rymai.me>

Include author in assignee dropdown search

## What does this MR do?

Previously when you searched for the author in the assignee dropdown (if they aren't in the project) it did not actually include the author. This changes that so that when you search for the author it will correctly include the user.

## Screenshots (if relevant)

![Screen_Shot_2016-11-17_at_11.14.53](/uploads/5a13475d8ded459fd3b1ba6570897665/Screen_Shot_2016-11-17_at_11.14.53.png)

## What are the relevant issue numbers?

Closes #22905

See merge request !7526