Add CI example for Play/Scala apps with deployment to Heroku

Replaces https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3204

See merge request !7574

[ci skip]

Add environment info to builds page

![Screen_Shot_2016-11-02_at_5.44.01_PM](/uploads/3443d9518997147d1e6f41830e3774ff/Screen_Shot_2016-11-02_at_5.44.01_PM.png)

Closes #23205

See merge request !7251

Pass correct tag target to post-receive hook when creating tag via UI

Fixes #24437

See merge request !7556

Fix migration missing ignored transaction method

Adds missing `disable_ddl_transaction!` to migration

See merge request !7569

Add JIRA remotelinks and prevent duplicated closing messages

implements #13232  
closes #20479   

See merge request !7413

Fix misaligned buttons on admin builds page

## What does this MR do?
Fix misaligned buttons on admin builds page

## Are there points in the code the reviewer needs to double check?
No

## Why was this MR needed?
Because buttons are misaligned.

## Screenshots (if relevant)
![fix-admin-ci-table](/uploads/49472f7a12f868556e1bf482c9f837c4/fix-admin-ci-table.gif)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Fixes #24371

See merge request !7424

We need to handle annotated tags that are created via GitLab UI.
Annotated tags have their own SHA. We have to pass this SHA to
post-receive hook to mirror what happens when someone creates
an annotated tag in their local repository and pushes it via
command line.
In order to obtain tag SHA we first have to create it. This is
a bit confusing because we create the tag before executing
pre-hooks, but there is no way to create a tag outside the
repository. If pre-hooks fail we have to clean up after ourselves.

Correct curl examples for archive and unarchive project API

[ci skip]

See merge request !7559

Cycle Analytics: Events per stage

Adds list of events to each stage:

- Issue: list of issues created in the last XX days, that have been labeled or added to a milestone.
- Plan: list of commits that reference for the fist time an issue from the last stage.
- Code: list of MR created in this stage
- Test: List of unique builds triggered by the commits.
- Review: List of MR merged
- Staging: List of deployed builds
- Production: list of issues with the time from idea to production

Fixes #23449 

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !6859

More aggressively preload on merge request and issue index pages

See merge request !7564

Remove race condition while deleting groups

## What does this MR do?

The intended flow during a group deletion is:

```
  Soft-delete group (sync) -> Delete group projects (async) -> Hard-delete group (async)
```

The soft-delete was run in a transaction, which was committed only after
the async job (for hard-deletion) was kicked off. There was a race
condition here - the soft-delete transaction could complete _after_ the
hard delete completed, leaving a soft-deleted record in the database.

This MR removes this race condition. There is no need to run the
soft-delete in a transaction. The soft-delete completes before the async
job is kicked off.

This MR also adds a migration to delete all existing (soft-deleted) groups left in an inconsistent state
due to this bug.

- Closes #23223 
- EE merge request: gitlab-org/gitlab-ee!886

See merge request !7528

Fix Admin Links to new Group does not respect Default Visibility

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/19981

See merge request !7560

Add changelog entry for 7251

See merge request !7543

Pipelines page redesign

Closes #23637
![Screen_Shot_2016-11-15_at_1.36.34_PM](/uploads/edc6a58f00cca3e03ffd1689bd6eebd8/Screen_Shot_2016-11-15_at_1.36.34_PM.png)

See merge request !7487

Settings

This is done by passing a visibility_level option to the group edit _form.
The visibility_level is set to @group.visibility_level in edit ation and
to default_group_visibility in the new action.

[ci skip]

Grapify repository api

See merge request !7534

Use the public CE repo URL instead of the one used in the runner

See the commit message to understand the reason of this change.

See merge request !7555

Allow registering users where the username contains dots (.)

## What does this MR do?

- Allow registering users whose usernames contains dots `.`
- This can currently be done by registering with a username containing no dots, and then editing the username to have dots in the user's profile settings.

## Does this MR meet the acceptance criteria?

-  [#24276/!7500] Unable to register names with dot
    - [x]  Implementation
    - [x]  Tests
        - [x]  Added
        - [x]  [Passing](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/7500/builds)
    - [x]  Meta
        - [x]  CHANGELOG entry created
        - [x]  Documentation created/updated
        - [x]  API support added
        - [x]  Branch has no merge conflicts with `master`
        - [x]  Squashed related commits together
    - [x]  Review
        - [x]  Endboss
            - [x]  Use `Gitlab::Regex::NAMESPACE_REGEX_STR` instead of a hardcoded pattern
            - [x]  Define `NAMESPACE_REGEX_STR` in terms of `NAMESPACE_REGEX_STR_JS`
    - [ ]  Wait for merge


## What are the relevant issue numbers?

- Closes #24276

See merge request !7500

Check all namespaces on validation of new username.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24519 and https://gitlab.com/gitlab-org/gitlab-ce/issues/24580

See merge request !7537

- Use multiple threads / database connections to:

  1. Escape the transaction the spec seems to be running
     in (`config.use_transactional_fixtures` is off, but
     `ActiveRecord::Base.connection.open_transactions` is not empty
     at the beginning of the spec.

  2. Simulate a Sidekiq worker performing the hard delete outside of the
     soft-delete transaction.

- The spec is a little clunky, but it was the smallest thing I could get
  working - and even this took a couple of hours. Let me know if you
  have any suggestions to improve it!

The intended flow is:

  Soft-delete group (sync) -> Delete group projects (async) -> Hard-delete group (async)

The soft-delete was run in a transaction, which was committed only after
the async job (for hard-deletion) was kicked off. There was a race
condition here - the soft-delete transaction could complete _after_ the
hard delete completed, leaving a soft-deleted record in the database.

This commit removes this race condition. There is no need to run the
soft-delete in a transaction. The soft-delete completes before the async
job is kicked off.

The database should not have any soft-deleted groups. Due to a race
condition (soft-delete completes after the hard-delete), soft-deleted
groups were (incorrectly) left in the database, causing issues while
trying to create a new group with the same name.

Fix wrong link URL

See merge request !7554

[ci skip]

Grammar fix in environments.md: s/base/basis

See merge request !7552

[ci skip]

[ci skip]