Rescue database error

We need to check which database is setup but we cannot assume that the database exists already. Not checking this will break rake gitlab:setup for packaging as we need to do asset precompile before the database exists.

See merge request !1393

Enable signup by default

See merge request !1394

Doorkeeper update

https://gitlab.com/gitlab-org/omnibus-gitlab/issues/398

See merge request !1392

Gitlab shell bump

See merge request !1391

OAuth2 API documentation

https://dev.gitlab.org/gitlab/gitlabhq/issues/1713

See merge request !1388

Conflicts:
	app/helpers/projects_helper.rb

Prose requirement

Feel free to improve or link to authoritative source.

See merge request !285

Improve readme to website

addresses some of https://dev.gitlab.org/gitlab/organization/issues/100.

See merge request !1355

First entry in wiki history leads to newest revision.

Scroll below the navbar

Fixes #1866

Show the markdown anchors by scrolling below the fixed top navbar.

See merge request !1390

Git HTTP blacklist

See merge request !1328

Add Changelog Guidelines to monthly.md

Fixes #1868

Added the changelog guidelines according to the issue mentioned above. @sytse I didn't add the extra lines to the 7.7.0 log, since we have a codefreeze soon.

/cc @job

See merge request !1389

Added DISCLAIMER to CHANGELOG

 ForbiddenAction constant name fix

See merge request !1387

Refactor push data builder

See merge request !1384

Mr widget remove source branch checkbox

Fixes #1858

Renamed custom `checkbox` css class for remove source branch checkbox because it was being overwritten on Safari by `checkbox` from bootstrap in `_forms.scss`

After rename, alignment looks corrected

See merge request !1386

Add search option to project api

When using Ajax to search for users authorised projects we need to do a search query on the returned list rather than doing a request using `/search/:query` option.

This MR also adds a simple spec for project ordering feature that got added in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/266 but no specs were provided.

See merge request !1385

Rename the checkbox css class to prevent it from being overwritten by the same named bootstrap class.