Instrument GitLab Shell and log metrics data to a file

See merge request !98

Test against ruby 2.3

Closes #61

See merge request !99

Fix rsync with ionice command building

See merge request !97

Fix short circuit logic between rsync with and without ionice for storage migrations

See merge request !96

storage migrations

Re-exposing GL_ID to custom hooks

closes https://gitlab.com/gitlab-org/gitlab-ee/issues/995
closes https://gitlab.com/gitlab-org/gitlab-shell/issues/53

See merge request !95

Update VERSION

Was this an oversight? Should we re-tag v3.6.2? Or just bump to v3.6.3?

See merge request !94

Enable GIT_TRACE_PERFORMANCE through a config variable.

The value of the variable must an absolute path needs to exist so we’re able to check if we can write in that file. Because in the 
case we cannot write we’ll throw a warning to the output of the users.

```sh
~/dev/gitlab/local/pacoguzman/gitlab-ce (master=)$ git push origin master
warning: could not open '/wadus' for tracing: Permission denied
Everything up-to-date
```

Closes #59

See merge request !91

Enable GIT_TRACE/GIT_TRACE_PACKET/GIT_TRACE_PERFORMANCE by providing the git_trace_log_file config key

The value of the variable if present must be a writable absolute path. If it’s
not the case we log a proper message and not enable tracing to not throw output to the users.

Set a low IO priority for storage moves to lower performance impact

See merge request !92

Added LFS support to SSH

Required changes to GitLab Shell include the actual handling of the `git-lfs-authenticate` command and the retrieval of the correct credentials.

Needed for gitlab-org/gitlab-ce!6043

Related to gitlab-org/gitlab-ce#3589

> **Note:** gitlab-org/gitlab-ce!6043 needs to be merged before this one.

cc @jacobvosmaer-gitlab @marin @DouweM

See merge request !86

- Required changes to GitLab Shell include the actual handling of the `git-lfs-authenticate` command and the retrieval of the correct credentials.

Add option to recover 2FA via SSH

Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/3765

Allow users to recover their own account if they lose their 2FA device or recovery codes. 

## Questions/Concerns

- Does this look secure? I think it is but we need to make sure no one can spoof a username or something and disable two factor.

## Todo

- [x] Working code
- [x] Tests
- [x] GitLab merge requests (including documentation)

![Screen_Shot_2016-08-18_at_2.34.18_PM](/uploads/1ed00e93abdfc3b41187c021e4f9d4db/Screen_Shot_2016-08-18_at_2.34.18_PM.png)

See merge request !74

Sentinel Support

Sentinel connection parameters in `config.yml` file.

Fixes #29

See merge request !85

In order to use chomp! on the input later, we need to dup the ARGV input string for keys

Also updated the gitlab_key tests to freeze the ARGV variables.

Fixes https://gitlab.com/gitlab-org/gitlab-shell/issues/56

See merge request !84

Show Merge request link after pushing if new brach

This is part of implementation for issue https://gitlab.com/gitlab-org/gitlab-ce/issues/18266

See merge request !77

update spec

different text for new and existing merge request

update spec

fix style

switch order of messages

enhance message appearance

remove extra spaces