Add option to restrict merge MR with failed build

_Originally opened at !3828 by @ruianderson._

-----

## What does this MR do?

This MR adds an option to prevent MR from being merged if their build status is not a success. Please note that if the MR has no `ci_commit`, the MR can be merged (i.e. we don't enforce builds to be configured).

## Are there points in the code the reviewer needs to double check?

Probably the copy in the edit project's page and in the documentation.

## What are the relevant issue numbers?

Closes #5940.

## Screenshots

![only_allow_merge_if_build_succeeds](/uploads/bb43cf131f680c9af0eb2ea5155189e0/only_allow_merge_if_build_succeeds.png)

See merge request !4503

Signed-off-by: Rémy Coutable <remy@rymai.me>

The logic of the method was obviously inverted.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Based on the feedback from reviewers.
Signed-off-by: Rémy Coutable <remy@rymai.me>

Signed-off-by: Rémy Coutable <remy@rymai.me>

Don't require Gitlab::Redis in mail_room.yml if it's already defined

## What does this MR do?

Avoid requiring `lib/gitlab/redis.rb` if `Gitlab::Redis` is already defined.

## Are there points in the code the reviewer needs to double check?

No.

## Why was this MR needed?

Because otherwise you get `already initialized constant Gitlab::Redis::XXX`, e.g.:

```
› bin/rspec spec/config/mail_room_spec.rb
Running via Spring preloader in process 24658
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:3: warning: already initialized constant Gitlab::Redis::CACHE_NAMESPACE 
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:3: warning: previous definition of CACHE_NAMESPACE was here
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:4: warning: already initialized constant Gitlab::Redis::SESSION_NAMESPACE
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:4: warning: previous definition of SESSION_NAMESPACE was here
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:5: warning: already initialized constant Gitlab::Redis::SIDEKIQ_NAMESPACE
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:5: warning: previous definition of SIDEKIQ_NAMESPACE was here
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:12: warning: already initialized constant Gitlab::Redis::URL_MUTEX
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:12: warning: previous definition of URL_MUTEX was here
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:13: warning: already initialized constant Gitlab::Redis::POOL_MUTEX
/Users/remy/Code/GitLab/gdk/gitlab/lib/gitlab/redis.rb:13: warning: previous definition of POOL_MUTEX was here
 2/2 |================================================= 100 =================================================>| Time: 00:00:00 

Finished in 0.38505 seconds (files took 0.48292 seconds to load)
2 examples, 0 failures
```

## What are the relevant issue numbers?

None!

## Does this MR meet the acceptance criteria?

- [x] ~~[CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added~~ Not needed.
- [x] ~~[Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~ Not needed.
- [x] ~~API support added.~~ Not needed.
- [x] ~~Tests.~~ Not needed.
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !4586

Signed-off-by: Rémy Coutable <remy@rymai.me>

Add Issue/PR Templates to deter issues/contributions on the GitHub mirror of the project

## What does this MR do?
Adds GitHub-specific `ISSUE_TEMPLATE.md` and `PULL_REQUEST_TEMPLATE.md` files in a `.github` directory. To prevent new issues/PRs, I figured it'd be good to direct users/contributors to open issues/contribute code in the "correct" project.

## Are there points in the code the reviewer needs to double check?
Wording/phrasing, mostly.

## Why was this MR needed?
The GitHub issue tracker is being closed, and PRs on GitHub haven't been accepted for a while now. This was discussed briefly during the GitLab Strategy Session at the Austin Summit.

cc: @dzaporozhets @rymai  @MrChrisW @dblessing @virtuacreative @amara  

See merge request !4324

Enable RuboCop for migrations

## What does this MR do?

Enable RuboCop for all files inside `db/migrate`, then add magic comments to all existing files, so that this only affects new migrations.

## Are there points in the code the reviewer needs to double check?

This entire change is a config change and a bunch of comments.

## Why was this MR needed?

```
Yorick Peterse [11:55 AM]  
I don't think we have any use case for nested def, might as well blacklist it

Sean McGivern [11:57 AM]  
http://www.rubydoc.info/gems/rubocop/RuboCop/Cop/Lint/NestedMethodDefinition

Sean McGivern [11:57 AM]  
hmm, it's already enabled

Sean McGivern [11:57 AM]  
... because we exclude `db/` from rubocop 🙂

Douwe Maan [11:57 AM]  
@smcgivern: heh

Sean McGivern [11:59 AM]  
I guess that's because we don't want to change the old migrations? I wonder if it's worth enabling it and adding magic comments to all the previous ones to ignore rubocop

Douwe Maan [11:59 AM]  
@smcgivern: agreed
```

## What are the relevant issue numbers?

None.

## Screenshots (if relevant)

None, but if I remove the magic comment from the migration `20160416182152_convert_award_note_to_emoji_award.rb` I get:
```
$ be rubocop
Inspecting 1959 files
..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................W....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Offenses:

db/migrate/20160416182152_convert_award_note_to_emoji_award.rb:3:5: W: Lint/NestedMethodDefinition: Method definitions must not be nested. Use lambda instead.
    def up ...
    ^^^^^^

1959 files inspected, 1 offense detected
```

## Does this MR meet the acceptance criteria?

- [ ] [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)
- [ ] API support added
- [ ] Tests
  - [ ] Added for this feature/bug
  - [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !4559

Wrap all rate limiting logic inside GitHub API client

## What does this MR do?

Move the actual rate limiting logic to GitHub API to clean the code inside the GitHub importer, and avoid code duplication.

## Are there points in the code the reviewer needs to double check?

No there aren't.

## Why was this MR needed?

Avoid code duplication to handle API rate limit in every call to the GitHub API.

## What are the relevant issue numbers?

There are none.

## Screenshots (if relevant)

Not relevant.

See merge request !4552

Fix failing `EmailOnPush` spec.

Closes #18447 

- This should fix CI on master

/cc @smcgivern @ayufan @stanhu @pacoguzman 

See merge request !4582

Award emoji fixes

Fixes #18357 #18325 and #18424

See merge request !4550

yes -> true
no -> false
. frequent -> .frequent-emojis

[ci skip]

Properly quote table name in Rake task for MySQL and PostgreSQL compatibility

!4318 broke the gitlab:db:drop_tables functionality for PostgreSQL.
    
Closes #15259

See merge request !4577

Add milestone expire date to the right sidebar

## What does this MR do?
Shows milestone expire date tooltip in the sidebar. It also shows the tooltip when sidebar is collapsed.

## Are there points in the code the reviewer needs to double check?
`common_utils.js.coffee` and `milestones_helper.rb` should be reviewed deeply.

## What are the relevant issue numbers?
https://gitlab.com/gitlab-org/gitlab-ce/issues/17355

## Screencast
![zngAcytBWq](/uploads/bd8514506aa5010aef9b081455ee90af/zngAcytBWq.gif)

See merge request !4448

!4318 broke the gitlab:db:drop_tables functionality for PostgreSQL.

Closes #15259

Checks for undefined when inserting autocomplete into textarea

## What does this MR do?

Correctly checks for undefined before inserting anything into the textarea when using autocomplete. This happens because the loading indicator tries to insert `@undefined` which we dont want to insert.

See merge request !4561

Fix bug with SQL syntax error during backup restoration

## What does this MR do?
It properly escapes the table name in the `DROP TABLE IF EXISTS ...` statement used during restore of a backup.

## Are there points in the code the reviewer needs to double check?
Please check compatibility with PostgreSQL

## Why was this MR needed?
Fix an issue with backups can not be restored if MySQL is used as database for GitLab.

## What are the relevant issue numbers?
#15259 

## Screenshots (if relevant)
-

See merge request !4318

Fix empty user projects snippets list

## What are the relevant issue numbers?
Closes #17952 #17816 and  #17737 

cc: @lbennett  @jschatz1 

See merge request !4532

Improve ui consistency. Part 2

* Use responsive top-area on project branches and tags pages
* Use default button size in the content list controls
* Improve button margin for btn-grouped css class

For https://gitlab.com/gitlab-org/gitlab-ce/issues/18324

See merge request !4536

Improved the UX of issue & milestone date picker

## What does this MR do?

Improves the UX of the date picker on issue form & milestone form.

## What are the relevant issue numbers?

Closes #18198 

## Screenshots (if relevant)

### Issues

![Screen_Shot_2016-06-06_at_09.28.29](/uploads/d9c192dff0d8076adc3ed6f005ea3790/Screen_Shot_2016-06-06_at_09.28.29.png)

### Project milestones

![Screen_Shot_2016-06-06_at_09.28.18](/uploads/2d03d72791c5fc6badfadb975a85af2b/Screen_Shot_2016-06-06_at_09.28.18.png)

### Group milestones

![Screen_Shot_2016-06-06_at_09.28.05](/uploads/0f28532396a16e6fd48ddea784ca28e3/Screen_Shot_2016-06-06_at_09.28.05.png)

See merge request !4485

Only load Chart.js when necessary.

Only load Chart.js where it's used, namely the Graphs section. Follow up on !4394.

cc: @jschatz1 

See merge request !4516

Fix local timeago on user dashboard

## What does this MR do?
Fixes incorrect date times on tooltips on the dashboard page

## Are there points in the code the reviewer needs to double check?
Yes,  The tooltip has to be recreated again because we needed a custom CSS classname in order to fix the date being splitted into two lines.

## Why was this MR needed?
Because the datetimes were incorrect we have to have the same format for .timeago() instances.

## What are the relevant issue numbers?
#17607

## Screenshots (if relevant)

**Before**

<img src="/uploads/f40cd58e8086d9675262e98a1fe57885/Screen_Shot_2016-05-24_at_7.23.25_PM.png" width="705">

**After**

<img src="/uploads/bd48046ef11659cc742f827b3404fbcd/Screen_Shot_2016-05-24_at_7.22.29_PM.png" width="704">


See merge request !4285

Improve input padding, fix #18237.

## What does this MR do?
Improves horizontal padding for input fields.

## What are the relevant issue numbers?
#18237

## Screenshots (if relevant)

Before:

![Screen_Shot_2016-06-06_at_12.11.07_PM](/uploads/11d24c84e1ca8d268a5acc2b4e10bb77/Screen_Shot_2016-06-06_at_12.11.07_PM.png)

After:

![Screen_Shot_2016-06-06_at_12.10.38_PM](/uploads/cbb407d8fca1e8dc1ace2af6c0774181/Screen_Shot_2016-06-06_at_12.10.38_PM.png)

cc: @jschatz1 

See merge request !4489

Use warning color merge conflicts icon in MR status widget.

Fixes #18174 

### Before
![Screen_Shot_2016-06-06_at_18.00.56](/uploads/4a74b1710478daee5ee95b7c6b6a835f/Screen_Shot_2016-06-06_at_18.00.56.png)

### After
![Screen_Shot_2016-06-06_at_17.58.04](/uploads/28faefaebef30e4256390029c87b28bb/Screen_Shot_2016-06-06_at_17.58.04.png)

See merge request !4487

Closes #18198

Edit form background color on highlighted note

## What does this MR do?

Added white background to edit form when in a highlighted note

## What are the relevant issue numbers?

Closes #18101 

## Screenshots (if relevant)

![Screen_Shot_2016-06-02_at_11.24.20](/uploads/c7c7fe710aa74d86152a109560fd0ebe/Screen_Shot_2016-06-02_at_11.24.20.png)

See merge request !4435

Toggling a task in a description with mentions doesn't creates a Todo

When user toggle a task list item in a description with a mention it
does not create an unnecessary Todo for that mention.

Closes #14116

See merge request !4568

Blur button tags when pressed to remove the focus state.

## Before 

![pemnD5exKl](/uploads/333155bf4a6c43715f3fc04d8f5aa35e/pemnD5exKl.gif)


## After

![dCPvSwsuWp](/uploads/9bcfbe59ac8de51e9d2c3edcb3d13ff3/dCPvSwsuWp.gif)

See merge request !4418