change mysql to postgres in some of the docs and scripts

* update deploy.sh, install gem without mysql, now that we want to use postgres instead
* update update_patch.md to assume postgres before mysql
* update ruby.md, to assume postgres

Add index_merge_request_diffs_on_merge_request_id

Added executable file permission to binstubs

Link to consolidated website with https links. Fixes #6017

Feature: reopen closed merge request

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

Added option to remove issue assignee on project issue page and issue ed...

Convert all help files to markdown files in doc directory

Backup Uploads Symlink

DB Reaping Frequency

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

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

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

Thanks to @jojosch for the initial work on the web-hooks.html.haml file!

Files moved:
* Workflow
* help/ssh
* help/webhooks
* help/system_hooks
* help/public_access
* help/permissions

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

Fix Backup Spec

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

fixed typo at the user management help page

Assuming that VERSION != VERSION.reverse is not robust. This will fail
at e.g. version 6.6.6.

Issue Improve Ui

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

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

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

Postgres fixes

For applications migrated from MySQL to PostreSQL it fixes some issues
Fixes #1060

 Use new gitlab_git gem. It makes CONTRIBUTING.md work

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

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