Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Add option to mirror an upstream repository.

Closes internal https://dev.gitlab.org/gitlab/gitlab-ee/issues/279

Depends on gitlab-org/gitlab-shell!29

To do:

- [x] Decide on what user should be the author of the activity feed events. The initial project creator perhaps? That makes sense for personal projects, but less so for group projects, where it's even possible that the creator has since left the team.
- [x] Write specs!
- [x] Write documentation
- [x] Port back relevant commits to CE: gitlab-org/gitlab-ce!1822

----

## Mirror status on project homepage

![Screen_Shot_2015-11-12_at_12.48.15](/uploads/39666b0e4a14723407b0f66e2aaddb46/Screen_Shot_2015-11-12_at_12.48.15.png)


## Settings navigation item

![Screen_Shot_2015-11-10_at_17.32.27](/uploads/116ece85f65681bbd3c7c5e282ab3b3c/Screen_Shot_2015-11-10_at_17.32.27.png)

## Mirroring settings

![Screen_Shot_2015-11-17_at_11.17.17](/uploads/ff57c89831524435ec6a063c3c470203/Screen_Shot_2015-11-17_at_11.17.17.png)


## Activity feed with new "pushes" (mirror updates)
![activity_feed](/uploads/04754251f2142fd06b1fddc2aae45232/activity_feed.png)

I have yet to decide on what user should be the author of these events. The initial project creator perhaps? That makes sense for personal projects, but less so for group projects, where it's even possible that the creator has since left the team.

## Warning that branch has diverged from upstream
![diverged](/uploads/ecf7ae6c5709f626c750695f45ca521a/diverged.png)

## Commits heading after failed update
![commits_failure](/uploads/d1b3e1f6796431c839ee9e2f67499283/commits_failure.png)

Link send user to the mirroring settings if they are a project admin.

## Mirroring settings after failed update

![Screen_Shot_2015-11-12_at_12.43.09](/uploads/ece68d5021c9a4c374bf6d973cf9fafa/Screen_Shot_2015-11-12_at_12.43.09.png)

## New project page
![new_project](/uploads/296beb6c7faf390a9b7e1facc9c1d4d6/new_project.png)

## Import form after failed import
(Screenshot outdated)

![new_import_failure](/uploads/ac0ebfc8ec23232603126fe0a6e10171/new_import_failure.png)

Shown when the initial import of a project fails, not when an update of an existing project fails.

cc @dzaporozhets @sytses @JobV

See merge request !51

Backport relevant changes from gitlab-org/gitlab-ee!51

To do:

- [x] Update gitlab-shell

See merge request !1822

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Closes #3311

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixed method to use git log via Popen as recommended, and made output match test (and thus system) expectations.

Include the log messages of recent commits in project-level search
results, providing functionality similar to 'git log --grep'.

Update repository model rspec tests to validate the output of
Repository#commits_with_log_matching.

Closes #3138

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Fixes #2526

Change "+" icon under "Files" section to have three options:

* Create file
* Upload file
* New directory

Upload file is no longer accessible from the "Create file" page.
Users can now select a target branch in upload file as well.

Closes #2799: Fixes a bug where file modes were overwritten after a commit

Closes https://github.com/gitlabhq/gitlabhq/issues/8253: Existing files
can no longer be overwritten in the "Create file" section.

Closes #2557

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>