Ensure that is no pending migrations when using database on
Gitlab::CurrentSettings

This fixes the undefined method `recaptcha_enabled' for
#<ApplicationSetting:0x007f28552f8238> when running the build.

See merge request !2254

Added additional config environmental variables to help Debian packaging

* GITLAB_EMAIL_FROM
* GITLAB_EMAIL_DISPLAY_NAME
* GITLAB_EMAIL_REPLY_TO

This is a followup on https://gitlab.com/gitlab-org/gitlab-ce/issues/3717

See merge request !2251

* GITLAB_EMAIL_FROM
* GITLAB_EMAIL_DISPLAY_NAME
* GITLAB_EMAIL_REPLY_TO

Hotfix for builds trace data integrity

Closes #4246

See merge request !2224

Fixes problem with user autocomplete URI 

```
Failed to load resource: net::ERR_NAME_NOT_RESOLVED
http://autocomplete/users.json?search=&per_page=20&active=true&current_user=false
```

Fixes #4118, #4136

See merge request !2136

Fix project transfer e-mail sending incorrect paths in e-mail notification

The introduction of ActiveJob and `deliver_now` in 7f214cee caused a race
condition where the mailer would be invoked before the project was committed
to the database, causing the transfer e-mail notification to show the old
path instead of the new one.

Closes #4670

See merge request !2235

The introduction of ActiveJob and `deliver_now` in 7f214cee caused a race
condition where the mailer would be invoked before the project was committed
to the database, causing the transfer e-mail notification to show the old
path instead of the new one.

Closes #4670

[ci skip]

Revert upvotes and downvotes params back to MR API

issue https://gitlab.com/gitlab-org/gitlab-ce/issues/3672

See merge request !2212

See merge request !2239

This ensures we can still start up even when not connecting to a
database.

See merge request !2238

This removes the need for Sidekiq and any overhead/problems introduced
by TCP. There are a few things to take into account:

1. When writing data to InfluxDB you may still get an error if the
   server becomes unavailable during the write. Because of this we're
   catching all exceptions and just ignore them (for now).
2. Writing via UDP apparently requires the timestamp to be in
   nanoseconds. Without this data either isn't written properly.
3. Due to the restrictions on UDP buffer sizes we're writing metrics one
   by one, instead of writing all of them at once.

Newlines aren't really needed and they may mess with InfluxDB's line
protocol.

Downcased user or email search for avatar_icon.

GitLab users are defined with their mail address which is enforced to be lower case. When a commit is listed in the history whose committer mail address is not written in all lower case, the corresponding GitLab user won't be found because the search is case sensitive resp. the mail address to search for not downcased.

Closes #3780 

See merge request !2234

Makes reCAPTCHA configurable through Application Settings screen

Following the work made by @stanhu here: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/2216, made it configurable without needing to restart Gitlab

See merge request !2231

This is a temporary hotfix that allows to access build artifacts created
before 8.3. See #5257.

This needs to be changed after migrating CI build files.

Note that `ArtifactUploader` uses `artifacts_path` to create a storage
directory before and after parsisting `Ci::Build` instance, before and
after moving a file to store (save and fetch a file).

Fix spelling mistake, thanks Connor.

[ci skip]

See merge request !2227

Signed-off-by: Rubén Dávila <rdavila84@gmail.com>

Handle missing settings table for metrics



See merge request !2232

Fix broken link in permissions page



See merge request !2233

This ensures we can still boot, even when the "application_settings"
table doesn't exist.

Move InfluxDB settings to ApplicationSetting

This moves the settings from the YAML files to the database.

cc @sytses

See merge request !2228

Fixed syntax in gitlab.yml.example



See merge request !2230

Restart settings are moved too.



See merge request !2226

Issue #4246

add issue weight to contributing

cc @dzaporozhets 

See merge request !2223

Storing of application metrics in InfluxDB

This adds support for tracking metrics in InfluxDB, which in turn can be visualized using Grafana. For more information see #2936.

See merge request !2042

Environment variables in the app

Fixes #3717 and #3519 

## Why environment variables?

We need environmental variables, they are an expected way to configure apps https://medium.com/@kelseyhightower/12-fractured-apps-1080c73d481c#.ntrdiyu4c

This causes many tools and to tutorials to make it easy to set environmental variables and harder to supply a configuration file. 

So even though we agree they are not ideal https://support.cloud.engineyard.com/hc/en-us/articles/205407508-Environment-Variables-and-Why-You-Shouldn-t-Use-Them the market has spoken.

## Why for GitLab the application and not for the Omnibus packages?

Environmental variables are also needed by people that do not run our Omnibus packages, for example natively bundled apps (Debian apt-get) and idiomatic Docker packages (Mesos, Kubernetes, etc.).

Of course it should work great with Omnibus packages too so any advise is welcome in that regard.

There is an MR https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/575/diffs to be able to set any variable in gitlab.rb via environmental variables. I think both that and this MR should be merged to solve the configuration problem for both Omnibus and non-Omnibus installations. When both are merged the documentation should be crosslinked.

## Why uppercase?

Need to be all cap according to Google Shell guideline:
"Constants and Environment Variable Names => All caps, separated with underscores, declared at the top of the file."
https://google.github.io/styleguide/shell.xml#Constants_and_Environment_Variable_Names

Or as explained on http://stackoverflow.com/a/673940/613240
Keeping to this convention, you can rest assured that you don't need to know every environment variable used by UNIX tools or shells in order to avoid overwriting them. If it's your variable, lowercase it. If you export it, uppercase it.

/cc @JobV @DouweM @marin @jacobvosmaer @ayufan @pravi

See merge request !2215