Improve Monokai highlight style to match original

The current monokai style in highlightjs is not very true to the
original and lacks colors for certain syntactic items. This change's
goal is to bring the highlightjs monokai style in line with the original
design from http://www.monokai.nl/blog/2006/07/15/textmate-color-theme/
Revert "Merge pull request #7349 from srna/patch-1"

This reverts commit b37b71d887e8521b8992aa6e4f789a38b393e55a, reversing
changes made to 42a1d8083c77d3803320bbbd0ac1559ff32d2519.
Add an avatar_url spec when relative url is set.
Prevent 500 on MR page if merge_event missing

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Decline push if repository does not exist

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Wait 15 minutes before Sidekiq MemoryKiller action
Bolder event title and lighter color for event body

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Move sidekiq debug docs to development folder
Execute project services asynchronously

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>
Merge branch 'async-services' into 'master'

Async services

Fixes #1814

See merge request !1312
Merge branch 'small-fixes' into 'master'

Small fixes

Improve application stability over unexpected cases

See merge request !1310
Merge branch 'improve-activity-ui' into 'master'

Improve activity UI

See merge request !1311
Merge branch 'improved-monokai' into 'master'

Improve Monokai highlight style to match original

The current monokai style is not very true to the original and lacks colors for certain syntactic items as mentioned in ticket https://github.com/gitlabhq/gitlabhq/issues/6855. This change's goal is to bring the monokai highlight style in line with the original design from http://www.monokai.nl/blog/2006/07/15/textmate-color-theme/

Before:
![monokai-old](https://gitlab.com/uploads/klowner/gitlab-ce/ce96c7d7c2/monokai-old.png)

After:
![monokai](https://gitlab.com/uploads/klowner/gitlab-ce/b257a8143a/monokai.png)

See merge request !238
Merge branch 'attachment_url_shouldnot_be_overwritten' into 'master'

Attachment url should not be overwritten

Fixes #1786

See merge request !1308
Drop vagrant preference in issue tracker guidelines.
Merge pull request #8436 from Razer6/move_doc_to_folder

Move sidekiq debug docs to development folder
Use constants instead of getters
Merge branch 'tracker_guidelines' into 'master'

Drop vagrant from issue tracker guidelines

Is this the preferred method of reproducing an issue? If yes, disregard this MR.

\cc @sytses @marin

See merge request !255
Fix typo
Use the new SIDEKIQ_MEMORY_KILLER_MAX_RSS variable