Disable MySQL foreign key checks before dropping all tables

Fixes #20237. Disables MySQL foreign key checks before dropping all tables in a restore. MySQL doesn't honor `CASCADE` without a special flag when the database/tables are created. In order to drop the tables we need to disable foreign key checks. After the drop, re-enable the key checks.

WIP: Pending confirmation from customer that this fix works.

See merge request !5472
Signed-off-by: Rémy Coutable <remy@rymai.me>

Add iid to MR API response

## What does this MR do?

Adds `iid` parameter to the MR API docs.

## Why was this MR needed?

It is missing.

## What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/19578

## Does this MR meet the acceptance criteria?

- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)

See merge request !5468
Signed-off-by: Rémy Coutable <remy@rymai.me>

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

Use project ID in repository cache to prevent stale data from persisting across projects

See merge request !5460
Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix backup restore

## What does this MR do?

This MR fixes the backup restore task.

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

Whether the mode 0277 makes sense. (Group SUID + group/user read/write permissions)

## Why was this MR needed?

86359ec8 broke this, and it was not caught by any specs. Users would see:

```
Restoring repositories ...
rake aborted!
NameError: undefined local variable or method `repos_path' for #<Backup::Repository:0x00000007cea1d8>
/opt/gitlab/embedded/service/gitlab-rails/lib/backup/repository.rb:59:in `restore'
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:79:in `block (4 levels) in <top (required)>'
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/backup.rake:54:in `block (3 levels) in <top (required)>'
Tasks: TOP => gitlab:backup:repo:restore
(See full trace by running task with --trace)
```

## What are the relevant issue numbers?

#20188

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [ ] Added for this feature/bug
  - [x] 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 !5459
Signed-off-by: Rémy Coutable <remy@rymai.me>

Add branch or tag icon to ref in builds page

## What does this MR do?
Add branch or tag icon to ref in builds page

## Why was this MR needed?
It's currently missing but should be there

## What are the relevant issue numbers?
Closes #20139

## Screenshots (if relevant)
<img src="/uploads/fb5c9a285a1ce95c0aa8dfa5e32c5d7d/Screen_Shot_2016-07-22_at_9.14.39_AM.png" width="400px">

See merge request !5434
Signed-off-by: Rémy Coutable <remy@rymai.me>

Users can filter branches by name on project branches page

This MR aims to solve #18674 by adding the possibility to filter project branches by name

![Screen_Shot_2016-07-07_at_17.21.25](/uploads/b674765d2b1cb8a121c2101715a4568b/Screen_Shot_2016-07-07_at_17.21.25.png)

See merge request !5144
Signed-off-by: Rémy Coutable <remy@rymai.me>

Fixed issue with autocomplete search not working with enter key

## What does this MR do?

Fixes an issue that was stopping the enter key from searching in the top search bar.

## What are the relevant issue numbers?

Closes #20165 

ps. Once this is merged - i'll create a MR against master with the JS changes.

See merge request !5466

Closes #20165

[8.10] Don't show comment button in gutter of diffs on MR discussion tab

`8-10-stable` counterpart to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5492

See merge request !5493

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

Add links to the real markdown.md file for all GFM examples

## What does this MR do?

Add links to the real markdown.md file for all GFM examples since they will not render correctly on docs.gitlab.com.

We already have a note https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/5440, but better be explicit.

See merge request !5458
Signed-off-by: Rémy Coutable <remy@rymai.me>

See !5454.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix bug where replies to commit notes displayed in the MR discussion tab wouldn'…

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/20157

See merge request !5446
Signed-off-by: Rémy Coutable <remy@rymai.me>

Fix Error 500 when creating Wiki pages with hyphens or spaces

- Closes gitlab-com/support-forum#874
- Closes #20209

See merge request !5444
Signed-off-by: Rémy Coutable <remy@rymai.me>

Add detailed info on storage path mountpoints

Users that run GitLab from source should be extra careful when using the
multiple repository storage feature. Make sure there is a detailed explanation
why this happens and how to overcome it.

See merge request !5437
Signed-off-by: Rémy Coutable <remy@rymai.me>

Gracefully handle case when keep-around references are corrupted or exist already

We were seeing a number of error messages when attempting to create a keep-around ref:

1. Failed to create locked file `refs/keep-around/XYZ`: File exists
2. Failed to write reference `refs/keep-around/XYZ`: a reference with that name already exists.

I'm not sure how these happen, but I suspect when multiple workers attempt to write the same file we may have an issue. The force parameter should help ensure the file gets created,
as well as the rescues to prevent 500 Errors.

Rugged/libgit2 unfortunately does not allow you to delete or re-create a reference that has been corrupted, even with the force parameter. A truncated reference will stay that way until manual intervention.

Closes #20109

See merge request !5430
Signed-off-by: Rémy Coutable <remy@rymai.me>

Refactor repository storages documentation

Use detailed information on using the multiple repository storage feature

See merge request !5428
Signed-off-by: Rémy Coutable <remy@rymai.me>

Make Notify specs more robust by setting up assignee names

Closes #20121.

See merge request !5427

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

Refactor Slack service documentation



See merge request !5421

Move admin application settings to own path

Move existing documentation to its own `user/admin_area/settings` path.

See merge request !5420

Refactor protected branches documentation

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/19832

See merge request !5419

Revert "Merge branch '17073-tagscontroller-index-is-terrible-response-time-goes-up-to-5-seconds' into 'master'"

This reverts commit be111259.

Add a spec for #20079

- This MR adds a spec for the fix for #20079 that was implemented in !5400.
- The spec is going in separately, just so the fix could go in as soon as possible.

See merge request !5414

Explain CI_PROJECT_NAMESPACE better

## What does this MR do?

Explain CI_PROJECT_NAMESPACE better by adding "The project namespace (username or groupname) that is currently being built".

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

Are `username` and `groupname` known words? We use it [here](http://docs.gitlab.com/ee/api/namespaces.html).

## Why was this MR needed?

Because `namespace` isn't a well known term.

## What are the relevant issue numbers?

## Screenshots (if relevant)


See merge request !5407

Simpler two queries than one JOIN with subquery

This is a follow up from !5347

Originally it was:

``` ruby
pipeline = pipelines.latest_successful_for(ref)
builds.where(pipeline: pipeline).latest.with_artifacts
```

However MySQL would complain that we can't use `IN` against a subquery which has `LIMIT`. Using `INNER JOIN` would be a workaround, however, doing that is too complicated in current version of Rails.

So let's just use two queries in this case.

Closes #14419

See merge request !5388

Merge branch '17073-tagscontroller-index-is-terrible-response-time-goes-up-to-5-seconds' into 'master'

Improve performance of tags controller

See merge request !5375

Fix a false positive where similar un-nested storage paths were reported as nested

Closes #19572

See merge request !5145

Change nav link snippet controller

Removes active Snippets nav link state for project-specific snippets

Closes #20046

See merge request !5410
(cherry picked from commit c53bd5a7)

Reduce min width of pipeline table

## What does this MR do?
Reduce min width of pipeline table

## Why was this MR needed?
The current min-width is based on the heavily populated pipelines page main table. This pipeline table doesn't have nearly as much information so can be collapsed down a lot further

![table](/uploads/895d2fb2f01383a841f973e918199f55/table.gif)
cc @markpundsack

See merge request !5409
(cherry picked from commit 95c4825a)

Avoid data-integrity issue when cleaning up repository archive cache

## What does this MR do?
Sets the default value for `repository_downloads_path` if someone has it configured incorrectly, and it points to the path where repositories are stored. It's also replace invocation of `find` with Ruby code that matches old cached files in a better, and safe way to avoid data-integrity issues.

## Why was this MR needed?
The `repository_downloads_path` is used by the `RepositoryArchiveCacheWorker` to remove outdated repository archives, if it points to the wrong directory can cause some data-integrity issue.

## What are the relevant issue numbers?
Closes #14222

See merge request !5285
(cherry picked from commit d2598f62)

Bump vmstat version to fix issues reporting on FreeBSD

Minor changes from 2.1.0 to 2.1.1:

https://github.com/threez/ruby-vmstat/commits/master

See merge request !5405
(cherry picked from commit 2cc3b893)

Don't drop in DropAndReaddHasExternalWikiInProjects

## What does this MR do?

This MR fixes the migration in question so it doesn't first drop and then re-add a column.

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

Not really.

## Why was this MR needed?

The old migration could lead to application errors as the column would temporarily not exist between the drop column and add column statements.

## What are the relevant issue numbers?

https://gitlab.com/gitlab-com/infrastructure/issues/239

## Does this MR meet the acceptance criteria?

- [x] ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~
- [x] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- [x] 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 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 !5402
(cherry picked from commit 2af769c3)

Don't use `params[:id]` while building `markdown_preview_path`.

- Closes #20079

See merge request !5400
(cherry picked from commit 2d7516ff)

UI bug fixes

Closes #20074
Closes #20094

Regression UI bug fixes
* Fix broken status icon on project page
* Center tooltip on empty state in pipeline
* Reduce max-width of commit title in pipeline so more fits in table
* Fixes firefox rendering (icons getting cut off)
* Fixes Safari rendering of SHA icon

See merge request !5383
(cherry picked from commit 0606b92c)