Fix a transient spec failure

Closes #24772 

See merge request !7825

Add StackProf to the Gemfile, along with a utility to get a profile for a spec

The test suite needs speeding up significantly. This is one tool for investigating it.

Related to #23034

See merge request !7784

Update Sidekiq-cron to fix compatibility issues with Sidekiq 4.2.1

The "Enqueue Now" button would not work in the admin panel due to changes in the Web extension interface: https://github.com/ondrejbartas/sidekiq-cron/commit/88ada926132d4658e3fd370c9f44899b6c88ccaf

Closes #24376

See merge request !7815

Add `null: true` to timestamps in migrations that does not define it

This is to ensure that migrations will still be consitent when we will
upgrade to Rails 5 which default to `null: false` for timestamps
columns.

Fixes #23666.

See merge request !7791

Alert user when logged in user email is not the same as the invitation

## What does this MR do?

Add a note to the invitation page when the logged in user email is not the same as the invitation.

## Why was this MR needed?

Help users to not accept invitations logged in with a wrong account.

## Screenshots (if relevant)

![1](/uploads/78ac6d3db67c9ed60cf74a20ad240d0b/1.png)

## Relevant issues

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24955

See merge request !7803

CE-specific changes for gitlab-org/gitlab-ee#1137

## What does this MR do?

- gitlab-org/gitlab-ee#1137 is a `technical debt` issue to clean up the EE protected branch access levels (for users and groups) implementation.
- Some of this cleanup bleeds over to code shared by CE and EE, which is why this MR is required.
- An EE-specific MR has also been created: gitlab-org/gitlab-ee!927

See merge request !7821

Fix the width of project avatars in order to adjust alignment within their container element

## What does this MR do?
Adjusts the width of project avatars in order to fix their alignment within the container elements.

## Are there points in the code the reviewer needs to double check?
To make sure there are no unintentional styles changes on unrelated elements.

## Why was this MR needed?
To fix the issue seen below.

## Screenshots (if relevant)
Before: ![Screen_Shot_2016-11-26_at_3.55.58_PM](/uploads/c0012ee7bb5f9e83af41190f71f030fa/Screen_Shot_2016-11-26_at_3.55.58_PM.png)

After: ![Screen_Shot_2016-11-26_at_3.56.17_PM](/uploads/c1236216382e6baa094570c17565e8cf/Screen_Shot_2016-11-26_at_3.56.17_PM.png)

Affected pages: ![Screen_Shot_2016-11-26_at_4.12.38_PM](/uploads/8db6d86a5998843e7b7a755fb4000add/Screen_Shot_2016-11-26_at_4.12.38_PM.png)

## What are the relevant issue numbers?
Closes #24999

See merge request !7772

Changes project dashboard tabs to sentence casing

Changes the nav tab titles on the project dashboard page (```https://gitlab.com/dashboard/projects```) from title casing to sentence casing.

Before: ![Screen_Shot_2016-11-26_at_11.17.23_PM](/uploads/a31c951cf83f7670acee778db9337be5/Screen_Shot_2016-11-26_at_11.17.23_PM.png)

After: ![Screen_Shot_2016-11-26_at_11.17.39_PM](/uploads/a0cb5f6b6771e6f5149750ea1e7beb02/Screen_Shot_2016-11-26_at_11.17.39_PM.png)

Closes #25002

See merge request !7774

Add blue back to sub nav active

## What does this MR do?
Adds blue color back active sub nav tab

## Screenshots (if relevant)
![Screen_Shot_2016-11-29_at_10.00.55_AM](/uploads/b968fce60d8e25e7f0769f6fb045291c/Screen_Shot_2016-11-29_at_10.00.55_AM.png)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
https://gitlab.com/gitlab-org/gitlab-ce/issues/24149

See merge request !7829

Adds hoverstates for collapsed Issue/Merge Request sidebar

This MR is part 1/2 of https://gitlab.com/gitlab-org/gitlab-ce/issues/25011

## What does this MR do?

Adds hoverstates for collapsed Issue/Merge Request sidebar

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


## Why was this MR needed?

We needed hover states on the issue/merge request sidebar

## Screenshots (if relevant)

![2016-11-27_23.39.28](/uploads/adb83f5fa291cc8f89f1a7d7e2577546/2016-11-27_23.39.28.gif)![2016-11-27_23.39.13](/uploads/7018e4272da26cb06efb7c6fe4eae413/2016-11-27_23.39.13.gif)

![2016-11-29_16.05.11](/uploads/fcf9a674aa24cf0e7349a7e439b024fe/2016-11-29_16.05.11.gif)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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
- [ ] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?


Closes #25011

See merge request !7777

New project should be below new group on the welcome screen

## What does this MR do?

Places the group `.blank-slate` above the project's.

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

## Why was this MR needed?

## Screenshots (if relevant)

![Screen_Shot_2016-11-26_at_13.52.33](/uploads/a6e28dc54ebfc42f0cff5b46558f4ff0/Screen_Shot_2016-11-26_at_13.52.33.png)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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
  - [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?


Closes #24135

See merge request !7770

Remove JSX/React eslint plugins.

## What does this MR do?

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

## Why was this MR needed?

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [ ] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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 [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?

See merge request !7470

Expose timestamps in build entity

## What does this MR do?

This MR exposes timestamps for build entity that is being used by serializers in `app/serializers`. 

## Does this MR meet the acceptance criteria?

- Tests
  - [x] Added for this feature/bug
  - [ ] All builds are passing

## What are the relevant issue numbers?

See https://gitlab.com/gitlab-org/gitlab-ce/issues/24844#note_19145053

See merge request !7818

Fix pipelines info being hidden in merge request widget

## What does this MR do?

Reintroduces CSS classes that are necessary for `MergeRequestWidget` to show correct divs.

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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~~
  - [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?

Closes #25055

See merge request !7808

Change airbnb eslint config package to `eslint-config-airbnb-base` and update plugins.

Change `airbnb` to `airbnb-base` for .eslintrc `extends` value.

Added changelog entry

Made sure all plugins and envs are set

Corrected new failing specs

Sorting by created_at can lead to uncertainties if two records are
created at the same time.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Remove unnecessary database indices

See merge request !7789

The "Enqueue Now" button would not work in the admin panel due to
changes in the Web extension interface.

Closes #24376

Fix broken README.md UX guide link.

See merge request !7805

Fix blob controller spec failure

See merge request !7814

Fix typos in Bitbucket integration docs

[ci skip]

See merge request !7823

- Extract all common {push,merge} access level model code into the
  `ProtectedBranchAccess` module

- Use the HTTP verb to define controller specs

Add setting to enable/disable HTML emails

Closes #24880

See merge request !7749

Add issue search slash command

See merge request !7752

Homogenize sort and filter dropdown toggles

## What does this MR do?

Homogenizes the style of *filter* and *sort* dropdown toggles (aka buttons) related to:
- *issues* (index, new & edit views)
- *issue boards* (index);
- *merge requests* (index, new, edit);
- *projects* (index and "explore");
- *projects admin* (index);
- *groups* (show and "explore");
- *groups admin* (index);
- *users admin* (index);
- *todos* (index);
- *branches* (index);
- *commits* (index);
- *cycle analytics*;
- *network*;
- *forks*;
- *tags* (index);
- *global search*

Some other dropdowns are incidently concerned:
- project admin (show);
- assigne/due date/milestone/label dropdowns on the issue and board sidebars;
- stage dropdown on the build sidebar;
- merge request and comparison dropdowns for choosing forks and branches;
- ref switcher (e.g. in the blob (show) view or in the graphs view);

Dropdown toggles concerned by #24150 but not covered in this MR:
- Dropdowns for selection MR versions to be compared (in the "Changes" tab of an MR);
- Dropdowns that bring up a list of actions:
  - "Settings" dropdowns (such as the one found on the upper-right corner of all project pages);
  - The download/action/notifications buttons on the main project page;
  - Dropdowns located inside of list items (on list of pipelines, users and groups, for instance);
  - The "Options" button on the commit (show) view;
  - The "+" button on the tree explorer (for creating files, branches, tags, ...)

### TODO
- [ ] Update ui.html if needed

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

Am I changing any other dropdown toggle than listed above?

## Why was this MR needed?

For #24150

## Screenshots (if relevant)

### Issue Index

**Before:**
![issue-index-before](/uploads/1aa358b0b9e79fd3a7467b57cd2b03ec/issue-index-before.png)

**After:**
![issue-index-after](/uploads/7a4159e8927d456ed3f4390072174e49/issue-index-after.png)

### Issue New

**Before:**
![issue-new-before](/uploads/fcfb9c39d2ff8f00827f52d60db5c114/issue-new-before.png)

**After:**
![issue-new-after](/uploads/a0b151d257d8f3e8f98a2873427362ee/issue-new-after.png)

### Merge Request Branch Selector

**Before:**
![merge-request-new-before](/uploads/8dd7b6e8ea38af7aced743386bfb83ca/merge-request-new-before.png)

**After:**
![merge-request-new-after](/uploads/38ad8f5a315344b3bab7e936a84acf7e/merge-request-new-after.png)

### Global Search
![global-search-after](/uploads/f2912b7d91fd286028cb9481d2d53a82/global-search-after.png)

### Cycle Analytics
![cycle-analytics-after](/uploads/248d5ca360bb510aa0f0bfa8a1a00aae/cycle-analytics-after.png)


## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) 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
- ~~Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)~~
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

#24150

See merge request !7583

Hide project variables values by default

Add a button to reveal/hide the values to help prevent accidental disclosure of sensitive information from wandering on a page.

![hide-vars](/uploads/5b5eeef9b4650776b529b780998bbb1b/hide-vars.gif)    

Closes #21358

See merge request !7731

Refactor issuable description and metadata form sections

Continuation of https://gitlab.com/gitlab-org/gitlab-ce/issues/23864.

Brother of gitlab-org/gitlab-ee!916.

See merge request !7758

Add diff hunks to notification emails

Add diff hunks to notification emails. Continued from https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5855 - thanks @hoopes!

This also fixes an issue where the + / - prefixes were missing from diffs in emails.

Screenshots (from my browser) of the HTML emails, along with text screenshots 😛

![image](/uploads/cb31400becf5149d40c8bb98a655aa93/image.png)

```
New comment for Merge Request !1 on app/views/admin/builds/index.html.haml:

http://localhost:3000/gitlab-org/gitlab-ce/merge_requests/1#note_1023

>          Finished

This is a comment at the top of a match section.
```

![image](/uploads/704dd3845797530697a27f5c1953c053/image.png)

```
New comment for Merge Request !1 on app/views/admin/builds/index.html.haml:

http://localhost:3000/gitlab-org/gitlab-ce/merge_requests/1#note_1022

>          Finished
>          %span.badge.js-running-count= @all_builds.finished.count(:id)
>  
> -    %li{class: ('active' if @scope == 'all')}
> -      = link_to admin_builds_path(scope: :all) do
> -        All
> -        %span.badge.js-totalbuilds-count= @all_builds.count(:id)
> -
>  .gray-content-block
>    #{(@scope || 'running').capitalize} builds
>  

This is a comment at the bottom of a match section.
```

![image](/uploads/4063f3d9738aea8ebf3c0e690d0eddee/image.png)

```
New comment for Merge Request !1 on app/views/admin/builds/index.html.haml:

http://localhost:3000/gitlab-org/gitlab-ce/merge_requests/1#note_1024

>          = link_to 'Cancel all', cancel_all_admin_builds_path, data: { confirm: 'Are you sure?' }, class: 'btn btn-danger', method: :post
>  
>    %ul.center-top-menu
> -    %li{class: ('active' if @scope.nil?)}
> +    %li{class: ('active' if @scope == 'all')}
>        = link_to admin_builds_path do
> +        All

This is a comment with some deleted and added lines above it.
```

Closes #21027, closes #24340.

See merge request !7660