Expanding documentation on how to contribute effectively to GitLab and
how to setup a development environment.

Allow /var/opt/gitlab/gitlab-shell to be a configurable path

Closes #1717

See merge request !1141

Resolve "Support gitlab-workhorse '-prometheusListenAddr' option (8.15)"

Closes #1751

See merge request !1139

Development docs for running a OpenShift dev environment

Development docs for running a OpenShift dev environment

See merge request !1059

And change the link to the docker store

Use human readable date and time format for naming db migration log files

Closes #1701

See merge request !1123

Fix a typo

See merge request !1137

Update GitLab in the OpenShift template to 8.14.1

And also made some fixes recommended by @jorgemoralespou

 - Drop the volume mount on the post-init container
 - Use a recreate deployment stragedy instead of rolling of supporting installs that have multiple nodes, but only allow one node to access a persistent volume at a time.

See merge request !1136

And also made some fixes recommended by @jmorales

 - Drop the volume mount on the pre-init container
 - Use a recreate deployment stragedy instead of rolling of supporting installs that have multiple nodes, but only allow one node to access a persistent volume at a time.

Fix Mattermost SSO setup

This is a proposed fix of #1217.


### Why the problem exists

As was investigated in #1217:
>   Mattermost is tried to be configured before database is ready.

This happens because Chef has _compilation_ and _execution_ phases of recipe. [Code here `/files/gitlab-cookbooks/gitlab/recipes/mattermost.rb:91-101`](https://gitlab.com/gitlab-org/omnibus-gitlab/blob/8-12-stable/files/gitlab-cookbooks/gitlab/recipes/mattermost.rb#L91-101) shows that `MattermostHelper.authorize_with_gitlab` is executed during _compilation_ phase, while databases are created during _execution_ phase.
As the result, it always fails to be configured at first run (which is common for running Docker containers).


### Proposed solution

Calling `MattermostHelper.authorize_with_gitlab` at _execution_ phase of Chef recipe.

See merge request !1109

[ci skip]

Signed-off-by: Rémy Coutable <remy@rymai.me>

Revert "Added default IPv6 configuration for NGINX"

This reverts commit 9b2adec0.

In order to fix the issues we've been encountering with users in ipv6

Fixes: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1735

See merge request !1133

This reverts commit 9b2adec0.

In order to fix the issues we've been encountering with users in ipv6

See: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1735

oc cluster up brings up a docker master node of openshift that uses
your local machine as a slave node.

Enable Mattermost slash commands by default

Slash commands are used for further integration with GitLab. This
feature however, is disabled by default by Mattermost and also in
gitlab-mattermost.

This commit will enable it by default, but only for new installs.

Fixes #1737 

See merge request !1128

Clean up apt lists to reduce the Docker image size

Signed-off-by: Tao Wang <twang2218@gmail.com>

See merge request !1129

Signed-off-by: Tao Wang <twang2218@gmail.com>

Updating GitLab Mattermost to 3.5.1 for GitLab 8.14.1 release

Mattermost 3.5.1 available now from https://www.mattermost.com/download/

This dot release addresses a security issue and multiple bugs found in the v3.5.0 release. Upgrading to Mattermost 3.5.1 is highly recommended.

You can visit https://gitlab.mattermost.com to verify and test the release.

[Full release notes can be found here](https://docs.mattermost.com/administration/changelog.html#release-v3-5-1). No changes are required for `gitlab.rb` and there are no changes to the Mattermost `config.json` from v3.5.0.

Please let me or @it33 know if you have any questions. Thanks!

See merge request !1127

Slash commands are used for further integration with GitLab. This
feature however, is disabled by default by Mattermost and also in
gitlab-mattermost.

This commit will enable it by default, but only for new installs.

Fix #1737

Added troubleshooting section to docs on using Docker Toolbox

Docker toolbox for Windows/Mac won't work for GitLab when using volumes
by default. You need to switch to Docker native, or use NFS mounts in the
boot2docker setup.

Related to comments in: https://gitlab.com/gitlab-org/omnibus-gitlab/issues/1601#note_18577412

See merge request !1126

Update git to 2.8.4.

I've checked [all release notes](https://github.com/git/git/tree/master/Documentation/RelNotes) between the two versions and nothing in there stood out as a breaking change.
This is safe to merge pending an internal event. It can be postponed to 8.15.

cc @gitlab-build-team

See merge request !1108