Merge branch 'artifacts' into 'master'

Implement Build Artifacts

This implements #3028 

1. It stores artifacts in shared/artifacts,
1. It adds `artifacts` to `.gitlab-ci.yml`,
1. We use GitLab Workhorse to offload artifacts uploading,
1. To download artifacts it uses GitLab Workhorse X-Sendfile extension,
1. There's one "artifact" per-build. The new upload removes previous one and creates a new one,
1. Default max artifact size is set to 100MB - this can be changed in settings.

Missing things:
1. Support for `.gitlab-ci.yml`: `artifacts: true or git-ls-files` which will upload all non tracked files,
1. Artifacts passing between builds.

GitLab Workhorse changes: https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/5
GitLab Runner changes: https://gitlab.com/gitlab-org/gitlab-ci-multi-runner/merge_requests/46

Syntax:
```
artifacts:
  untracked: true # default: false
  paths: # default: empty
  - bin/files
```


See merge request !1584

1 files changed, 1 insertions, 1 deletions

diff --git a/Gemfile b/Gemfile
index c73aa26bd0a..6ee0e4ae286 100644
--- a/Gemfile
+++ b/Gemfile
@@ -54,7 +54,7 @@ gem 'gollum-lib', '~> 4.0.2'
 gem "github-linguist", "~> 4.7.0", require: "linguist"
 
 # API
-gem 'grape',        '~> 0.6.1'
+gem 'grape',        '~> 0.13.0'
 gem 'grape-entity', '~> 0.4.2'
 gem 'rack-cors',    '~> 0.4.0', require: 'rack/cors'