It should not be a start to a new thread but rather
a reply to an existing thread

Do not disclosure merge request id via email for unauthorized users
when closing issues.

- Select notification email by walking up group/subgroup path
- Add settings UI to set group email notification address
- Add tests

Don't show new issue link after move
when a user does not have permissions
to display the new issue

Process CSV uploads async using a worker then email results

Also refactored issues and MRs to use the same email template file

This whitelists all existing offenses for the various CodeReuse cops, of
which most are triggered by the CodeReuse/ActiveRecord cop.

Adds `#build_notification_recipients` to `NotificationRecipientService`
that returns the `NotificationRecipient` objects in order to be able to
access the new attribute `reason`.

This new attribute is used in the different notifier methods in order to
add the reason as a header: `X-GitLab-NotificationReason`.

Only the reason with the most priority gets sent.

[ci skip]

1. Make the "subscribed" text in Issuable sidebar reflect the labels
   subscription status

2. Current user mut be logged-in to toggle issue/MR/label subscription

1. Allow subscribing (the current user) to a label

- Refactor the `Subscription` coffeescript class
  - The main change is that it accepts a container, and conducts all
    DOM queries within its scope. We need this because the labels
    page has multiple instances of `Subscription` on the same page.

2. Creating an issue or MR with labels notifies users subscribed to those labels

- Label `has_many` subscribers through subscriptions.

3. Adding a label to an issue or MR notifies users subscribed to those labels

- This only applies to subscribers of the label that has just been
  added, not all labels for the issue.

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

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

Make the following changes to deal with new behavior in Rails 4.1.2:

* Use nested resources to avoid slashes in arguments to path helpers.

* send a 'In-Reply-To' header along the 'References' header
* subject of answers to an existing thread begins with 'Re: '

This reverts commit 97fd990e, reversing
changes made to f451a697.

Conflicts:
	app/mailers/emails/notes.rb
	app/mailers/emails/projects.rb

* send a ‘In-Reply-To’ header along the ‘References’ header
* subject of answers to an existing thread begins with ‘Re: ’

This fixes threading with at least Mail.app and Airmail.

This fixes email threading in Mail.app, that doesn't like when a thread
doesn't have stable recipients.

For instance, here is a possible sender-recipient combinations before:

From: A
To: Me
New issue

From: B
To: Me
Reply on new issue

From: A
To: Me
Another reply

Mail.app doesn't see B as a participant to the original email thread,
and decides to break the thread: it will group all messages from A
together, and separately all messages from B.

This commit makes the thread look like this:

From: A
To: gitlab/project
Cc: Me
New issue

From: B
To: gitlab/project
Cc: Me
Reply on new issue

From: A
To: gitlab/project
Cc: Me
Another reply

Mail.app sees a common recipient, and group the thread correctly.

Added email threading for update emails on issues and merge requests (if the mail client support the References: mail header)

When an email notification concerns a specific object (issue, note,
merge request, etc.), add a link to the footer of the email that opens
the item's page in a web browser.

Rationale:

* The link is predictable: always the same text, always at the same
location, like any reliable tool.

* It allows to remove the inline-title in many emails, and leave only
the actual content of the message.

This changes the email "From" field from "gitlab@example.com" to either:

* "John Doe <gitlab@example.com>" if the author of the action is known,
* "GitLab <gitlab@example.com>" otherwise.

Rationale: this allow mails to appear as if they were sent by the
author. It appears in the mailbox more like a real discussion between
the sender and the receiver ("John sent: we should refactor this") and
less like a robot notifying about something.

This changes the email subjects for issues and merge request
notifications from:

    Team / Project | Note for issue #1234

to:

    Team / Project | Saving issue doesn't work sometimes (#1234)

Rationale:

* Scan the subject of the email notification more easily when catching
up with a lot of notifications. Instead of having to open the email to
get the title of the issue or merge request, one can simply read the
subject of the email.

* Group messages by subject: email clients will group emails in threads
if they have the same subject.

There was some funny syntax in merge request email templates. There was a ! before
the merge request number when there probably should be a #. This may be some carry over
from markdown but should not be in email templates.  There were also some capitalization
discrepancies among the subject lines. For those OCD people out there I standardized the
capitalization. :)