Add Sidekiq troubleshooting docs

Closes #15287 

cc/ @stanhu @jacobvosmaer @dstanley

See merge request !3802

Refactor Todos feature spec to be faster and less brittle

We now only create two Todos instead of 21 when testing pagination, and
we've updated the test to be less brittle when dealing with slower CI
environments.

See merge request !3889

Use the `can?` helper instead of `current_user.can?`

Fixes #15513.

See merge request !3882

We now only create two Todos instead of 21 when testing pagination, and
we've updated the test to be less brittle when dealing with slower CI
environments.

Correctly escapes label title in filters

Fixes #15522

See merge request !3880

Move cherry-pick feature specs to proper directory

Cherry pick feature specs were located in `spec/feature/project` directory while we have `spec/feature/projects`.

Later location is consistent with our namespaces (we have `Projects::` namespace, not `Project::`).

See merge request !3875

Bump gitlab-shell to 2.7.2

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15525

See merge request !3884

[ci skip]

Add tests for filtering owned projects

REF: #3799

See merge request !3873

Fixed issue with assignee object not being returned

Closes #15515

See merge request !3877

Fixes #15513.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Fixes #15522

Closes #15515

Allow filtering by Owned projects on dashboard page

Closes #3799 

![Screen_Shot_2016-04-15_at_9.40.52_PM](/uploads/440498c5647bda282304891307931a02/Screen_Shot_2016-04-15_at_9.40.52_PM.png)

See merge request !3762

Add newest enhancements to GH importer docs

[ci skip]

See merge request !3867

Improved email confirmation UX

Closes #4228

See merge request !3184

[ci skip]

Use new Note styleguide



See merge request !3866

Always read diff_view setting from the cookie

Prior, when the user had their view set to "parallel" and then visited a
merge request's changes tab _without_ passing the `view` parameter via
query string, the view would be parallel but the `Notes` class was
always instantiated with the default value from `diff_view` ("inline"),
resulting in broken markup when the form to add a line note was
dynamically inserted.

The cookie is set whenever the view is changed, so this value should
always be up-to-date.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/14557 and https://gitlab.com/gitlab-org/gitlab-ce/issues/15285

See merge request !3732

[ci skip]

Fix vulnerability that leaks private labels and milestones

## Summary

This fixes vulnerability that leaks information about private labels and milestones because of  insecure direct object reference in issueable create service.
This affects merge requests and issues.

See https://gitlab.com/gitlab-org/gitlab-ce/issues/15439

## Fix

This MR introduces additional check that rejects labels and milestone that does not belong to the same project issue/merg request does.

## Further work

`IssuableBaseService` may benefit from encapsulating filters in separate class/module, which then may improve coherency in this class.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15439

See merge request !1954

This also verify if milestone belongs to correct project before creating
a new issue.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15439

Closes #4228

Fixes text color on labels in sidebar

Previously the labels in the sidebar would just have `#FFF` text color which could cause problems with a light background color.

With this, the text color comes from the JSON.

See merge request !3846

Remove the `.distinct` when finding issues

See merge request !3858

Disable 'repository check' feature in 8.7.0

See merge request !3856

Removed JS update templates

See merge request !3814