refactor login as to be impersonation with better login/logout
Modifies the existing "login as" feature to be called impersonation.
This also adds:
* Application keep track of who is impersonating the user so they can revert back to the original user without having to log out.
* Stores the user profile via `HTTP_REFERER` so you get redirected back to the person you have impersonated once you stop.
## Screenshots:


See merge request !1702
Expose builds feature
Expose builds feature in project settings (as feature).
Enable it by default for a new projects.
I deliberately named it builds instead of CI, because we actualy allow to run tests using infrastructure built-in GitLab. I'm free to change it.

If we are ok, I'll add feature tests for it.
/cc @sytses @dzaporozhets
See merge request !1767
Refactor complex methods
Make flog part of CI check which is not allowed to fail. I used high score (70) and refactored most complex method. In future releases we should lower acceptable score to something like 40..50
Part of #3444
See merge request !1794
Allow to define cache in `.gitlab-ci.yml`
This extends `.gitlab-ci.yml` syntax to allow specifying caching files and directories between builds, making it easy to preserve ex. gems.
```
cache:
paths:
- .bundle
- vendor/
before_script:
- bundle install --path vendor/
rspec:
script:
- bundle exec rspec
```
This is based on Build Artifacts changes.
/cc@dzaporozhets
See merge request !1786
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
- Offloads uploading to GitLab Workhorse
- Use /authorize request for fast uploading
- Added backup recipes for artifacts
- Support download acceleration using X-Sendfile
Fix bug where manually merged branches in a MR would end up with an empty diff
This bug manifested in 8.1 with the refactoring of `RefreshService`. Here's what happens:
1. User create a new branch `foo`.
2. User creates a merge request for `foo`.
3. User merges `foo` into `master` by hand.
4. `RefreshService` reloads the merge request. Since `master` is equivalent to `foo`, this results in an empty diff.
5. `RefreshService` then closes the MR.
This wasn't an issue when you use the normal "Accept Merge Request" flow because the act of clicking the button closes the merge request, so step 4 never happens.
Closes#3314
See merge request !1758
- Add page titles to CI settings.
- Fix CI admin navigation.
- Remove duplicated scope.
- Use monospace font for commit sha.
- Add page title and header title to build page.
- Proper authorization for cancel/retry builds.
- Use gitlab pagination theme for builds and group members.
- Don't paginate builds widget on build page.
- Add badges to commit page Changes/Builds tabs.
- Add "Builds" to commit Builds tab page title.
- Add and use Ci::Build#retryable? method.
- Add CI::Build#retried? method.
- Allow all failed commit builds to be retried.
- Proper authorization for cancel/retry all builds.
- Remove unused param.
- Use time_ago_with_tooltip where appropriate.
- Tweak builds index text
- Remove duplication between builds/build and commit_statuses/commit_status.
- Use POST rather than GET for canceling and retrying builds.
- Remove redundant URL helpers.
- Add build ID to build page.
- Link branch name on build page.
- Move commit/:sha/ci to commit/:sha/builds.
Remove duplicate orders
This changes the default order from `created_at DESC, id DESC` to just `id DESC` as this achieves the same results without the overhead of having to sort data twice (we've seen queries go from 200ms to just a few ms by removing the double sort).
cc @jacobvosmaer @dzaporozhets @rspeicher @DouweM
See merge request !1735
Extend yml syntax for only and except to support specifying repository path
This allows to limit execution of jobs to specific repository.
For example:
```yaml
job:
only:
- branches@gitlab-org/gitlab-ce
except:
- master@gitlab-org/gitlab-ce
```
The above will run `job` for all branches on `gitlab-org/gitlab-ce`, except master.
@dzaporozhets @JobV @vsizov Please review.
See merge request !1720