Fix merge request lock problem

Merge Request lock problem
MR can be stuck in lock state if satelitte timeout >= unicorn timeout.

Issue explanation:

* Person press Accept button
* unicorn worker starts, lock MR and trigger satellite
* satellite does merge but very long (30 seconds)
* unicorn timeout reaches earlier then satellite timeout
* unicorn kills worker because of timeout leaving MR in lock state.

Fix:

* set locked_at date
* if MR was locked for too long - close it automatically

- - -

Fixes #1674

See merge request !1306

Add snapshot backup tips

See merge request !1307

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Release docs improvements

Fixes #1734

See merge request !1305

512mb memory description

See merge request !1297

Rake task for google email schema verfication

#1607

See merge request !1300

Dev rake task docs

As discussed in #1184

See merge request !1301

Refactor atom code

See merge request !1304

Atom feed for user

This feature allows to subscribe for users activity via atom feed.

See merge request !1303

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Sidekiq 2.17.8

See merge request !1277

Prevent 500 test webhook

Fixes #1803

See merge request !1299

Supporting for multiple omniauth provider for the same user

fixes https://dev.gitlab.org/gitlab/gitlabhq/issues/1721

and https://dev.gitlab.org/gitlab/gitlabhq/issues/1760

See merge request !1296

Write to log if web hook cant be executed. This prevents 500 error when
test web hook with invalid URL and prevent exceptions and retries in
sidekiq
Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Improve english wording in UI filters

Fixes #1664

See merge request !1298

Docker version upgrades

See merge request !251

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>