This greatly improves frontend rendering times.

Now it executes a single query instead of a possible three at the cost
of some scary-looking ARel calls.

Minor refactoring, add specs, changes arguments to use keywords.

Add 'proposed tweet' for RC1

See merge request !835

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

Conflicts:
	Gemfile.lock

Fix duplicate 'Email has already been taken' message when creating a user

devise :validatable and validates uniqueness set on the user email field cause 2 validations to fire when creating a new user with an email address already in use, Issue 6123

@stanhu Thanks for your input on merge request 807, I'll close that one in favour of this as I have added tests

See merge request !817

Prefix 2FA issuer with the GitLab host (e.g., 'dev.gitlab.org')

https://dev.gitlab.org/gitlab/gitlabhq/issues/2373

See merge request !821

added info about migrating to gitlab.com

Added useful information. Because of tweet https://twitter.com/A_Makedonsky/status/610860840036749314

See merge request !1870

Bump rails to 4.1.11, jquery-rails to 3.1.3

rails 4.1.11 notes - http://weblog.rubyonrails.org/2015/6/16/Rails-3-2-22-4-1-11-and-4-2-2-have-been-released-and-more/

jquery-rails < 3.1.3 security advisory: https://groups.google.com/forum/#!topic/ruby-security-ann/XIZPbobuwaY

See merge request !830

Random Bootlint fixes

See merge request !822

Support commenting on a diff in side-by-side view

### What does this MR do?

This MR adds support for commenting on a diff in side-by-side (aka parallel) view. It also fixes a JavaScript bug (see !779) when the comment button is clicked on a line that already has a comment.

There is an existing bug where the comment count is not updated when a new comment is added. I'll send a MR for that later.

### Why was this MR needed?

Commenting only worked in "inline" mode. Often the side-by-side view is more conducive to writing comments.

### What are the relevant issue numbers?

Closes https://github.com/gitlabhq/gitlabhq/issues/9283

### Screenshot

![image](https://gitlab.com/stanhu/gitlab-ce/uploads/3d0a3213fde38844a681a826da18139b/image.png)

See merge request !810

Closes https://github.com/gitlabhq/gitlabhq/issues/9283

If kerberos is enabled require it

Since 'group: :kerberos' got [included in the Gemfile ](https://gitlab.com/gitlab-org/gitlab-ce/commit/2391a43a7073b4e723e9ca1f7ff19b30f8e51452) Kerberos no longer got [loaded when the app started](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/config/application.rb#L6)

This caused `Devise::OmniAuth::StrategyNotFound` error once Kerberos is enabled, failing to start GitLab .

With this we hopefully do not need to remove group from the Gemfile.

See merge request !819

Fix layout issue in header title truncation.

@douwe Thanks for reviewing this fix for the issue mentioned in https://dev.gitlab.org/gitlab/gitlabhq/issues/2314#note_48539.

**BEFORE**

![before](https://dev.gitlab.org/gitlab/gitlabhq/uploads/4ffb35f77155a92c64cfe36c66987eb0/before.gif)

**AFTER**

![after](https://dev.gitlab.org/gitlab/gitlabhq/uploads/2bb2d0c4a93164f6d47e24cdcb9a106b/after.gif)

See merge request !1867

Fix UI issues in Applications form

@douwe Thanks for reviewing this small fix.

---

Before:

![application_form_before](https://dev.gitlab.org/gitlab/gitlabhq/uploads/11fbee17ad6a4c9456cd7d6cba5ae429/application_form_before.png)

---

After:

![application_form_after](https://dev.gitlab.org/gitlab/gitlabhq/uploads/0c64214ccda6c77095f468fcb8c748f3/application_form_after.png)

See merge request !1859

Fix hooks for web based events with external issue references

The creation of cross references for external issues (which would fail)
is now prevented. This fixes a 500 error and the execution of hooks when
creating a merge request or commenting on one.

Fixes #1650, GH-9333.

This regression might have been introduced by
8f8a8ab3. There is actually a TODO by
@rspeicher mentioning external issues which is lost (unhandled) in a
later commit.

This fix is related to !766 and !804 which fix a similar issue for hooks for
Git based events.

See merge request !794

Update release doc

See merge request !1865