Update Rails to 4.2.5.2

See https://groups.google.com/forum/#!msg/rubyonrails-security/ddY6HgqB2z4/we0RasMZIAAJ
and https://groups.google.com/forum/#!msg/rubyonrails-security/ly-IH-fxr_Q/WLoOhcMZIAAJ

See merge request !3020

See https://groups.google.com/forum/#!msg/rubyonrails-security/ddY6HgqB2z4/we0RasMZIAAJ
and https://groups.google.com/forum/#!msg/rubyonrails-security/ly-IH-fxr_Q/WLoOhcMZIAAJ

Created helper class to hide content in issue sidebar when collapsed

![Screen_Shot_2016-02-25_at_10.38.39](/uploads/ca49cc230edf7e71b7726e905f523092/Screen_Shot_2016-02-25_at_10.38.39.png)

Closes #13764

See merge request !2968

Fix order in Gemfile.lock

See merge request !2969

Does not create a Todo when commenting on commit or project snippet

Closes #13733

See merge request !2964

Move "I should see Crowd login form" feature to a view spec

We were doing all kinds of code gymnastics to "enable" Crowd in the
feature spec and this would sometimes cause a transient failure.

Really what it's testing is if the Crowd login form shows when Crowd's
enabled, so this is much better suited to a view spec.

See merge request !2963

Sidebar overlaps content when screen is below 1200px.

When screen is below 1200px, the sidebar overlaps.
When screen is above 1200px, the sidebar pushes content out.
z-index change to make sure hamburger stays on top.
Fixes #12717
![screensize](/uploads/9a21fa06d583a49d6ebbf1ada34c6792/screensize.gif)

![screensize-small](/uploads/7c25f46e962248a40840562a01c83f8f/screensize-small.gif)

Also sorry I couldn't get the collapse button in the screen cap. It's there.

See merge request !2620

Changed padding & background color for highlighted notes

Closes #12453

![Screen_Shot_2016-02-23_at_11.18.59](/uploads/19150d884fd1175fe0df5f6daee64206/Screen_Shot_2016-02-23_at_11.18.59.png)

See merge request !2937

Fixed revert button tooltip placement causing movement

Before:

![moving-tooltip](/uploads/65cb9a41e8b8114fd8ee10d68cfd8206/moving-tooltip.gif)

After:

![moving-tooltip](/uploads/a1c36eb5735dc7592c49f6b5cb1469b5/moving-tooltip.gif)

See merge request !2910

Fix group projects styles

Makes new project button visible when no projects are available.
Fixes #13193

![Screen_Shot_2016-02-04_at_1.08.27_PM](/uploads/36be9d5892506e7d1abcf4eb2a622e12/Screen_Shot_2016-02-04_at_1.08.27_PM.png)

![Screen_Shot_2016-02-04_at_1.07.48_PM](/uploads/fa257a1965017ff1274572dc66fccf90/Screen_Shot_2016-02-04_at_1.07.48_PM.png)

![Screen_Shot_2016-02-04_at_1.07.28_PM](/uploads/326f6fdac24b56e8408efd0d11dc2805/Screen_Shot_2016-02-04_at_1.07.28_PM.png)

cc @creamzy @skyruler

See merge request !2714

Fixed issue with content in the issue sidebar disappearing

Closes #13626

See merge request !2919

Revert "Remove newrelic gem. Closes #12860"

This reverts commit 53176717.

Conflicts:
	Gemfile.lock

See merge request !2943

Show Crowd login even when sign-in is disabled

Fixes #13176.

See merge request !2749

Does not raise an error when Todo  is already marked as done

Closes #13681

See merge request !2926

Update sentry-raven to 0.15.6

Fixes a few bugs, most notably (for our purposes): https://github.com/getsentry/raven-ruby/pull/450

See merge request !2947

Set of UI fixes

* Improve wiki pages
* Improve profile pages

cc @skyruler

See merge request !2758

Restrict permissions on public/uploads

Based on https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/631

See merge request !2764

Issues can be dragged & dropped into empty milestone lists

This is also possible with MRs. Also fixed an issue where MRs weren't sortable

Fixes #13668

![milestone](/uploads/aada0f48ce8b1407cce920eef3f4d5f3/milestone.gif)

See merge request !2935

Ensure we don't check a commit's description for revert message if it has no description

Fixes #13631.

/cc @razer6 @grzesiek @yorickpeterse @rdavila 

See merge request !2917

Fix Side-by-side view after loading diff results

Fixes #13463

See merge request !2880

Add when the API changes got introduced



See merge request !2912

Fixed failing issues tests

Also removed up/down vote icons from merge requests. Was missed from d8069bd8

See merge request !2911

[ci skip]

Only show up or down votes icon on issue list if there are any

Closes #13649 

![Screen_Shot_2016-02-22_at_10.20.27](/uploads/21477426856dab9731bb110032025867/Screen_Shot_2016-02-22_at_10.20.27.png)

See merge request !2909

Add Todos

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/2425

Tasks:

-  Prepare database
 - [X] Create a new table (`todos`)
- Tasks Queue view
 - [X] Add a number icon showing the number of todos on the top right next to the new and logout button that will redirect the user to the todos page
 - [X] Add a chronological list of todos, with the 'Todos' tab active by default
 - [X] Add a 'Done' button to each todo
 - [x] Add filters (project, author, type, and action)
- Todos generation
 - [X] When user issue/mr is assgined to someone
 - [x] When user is mentioned on (issues/mr's/comments)
- Mark todo as `done`
 - [X] When clicks on the 'Done' button
 - [X] When edit issue/mr
 - [X] When left/edit a comment
 - [X] When reassign issue/mr
 - [X] When add/remove labels to issue/mr
 - [X] When issue/mr is closed
 - [X] When mr is merged
 - [X] When added an emoji
 - [X] When changed the issue/mr milestone

* Screenshot:

![Screenshot_2016-02-20_12.45.57](/uploads/4b2554b1bde25aed3347e1ae41e8e0c0/Screenshot_2016-02-20_12.45.57.png)

See merge request !2817

Fix bugs in MergeWhenSucceeded

1. This fixes support for merge when succeeded for statuses without ref.
2. This fixes support for merge when succeeded for multiple stages. Stages are created after all builds for previous one are finished.

Fixes: https://gitlab.com/gitlab-org/gitlab-ce/issues/9060 https://gitlab.com/gitlab-org/gitlab-ce/issues/8108 https://gitlab.com/gitlab-org/gitlab-ce/issues/12931 https://gitlab.com/gitlab-org/gitlab-ce/issues/13269

/cc @grzesiek @DouweM @rspeicher 


See merge request !2894

Fix docs on artifacts API

Small fixes for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2893

- Backticks in parameters
- Remove headings
- Fix curl URL link



See merge request !2902

Award emoji supports retina displays

Based on discussion in !2800

There is now a retina spritesheet for emojis. It is 2mb, don't know how big an issue that is.

Before:

![Screen_Shot_2016-02-19_at_11.07.25](/uploads/ea412579bcaddfd13fce67bf583de61b/Screen_Shot_2016-02-19_at_11.07.25.png)

After:

![Screen_Shot_2016-02-19_at_11.07.36](/uploads/9d44c6278ba31987bad03dc1f46edd8b/Screen_Shot_2016-02-19_at_11.07.36.png)

Also updated the rake task to make the @2x spritesheet https://gitlab.com/snippets/15348

cc\ @rspeicher @vsizov 

See merge request !2891

Flush emptiness caches whenever needed



See merge request !2903

Introduce API for serving the artifacts archive

Add API to download build artifacts archive in context of GitLab API

/cc @DouweM @grzesiek 

See merge request !2893

Add documentation about build emails service

Closes #12497

See merge request !2871