Merge branch 'multiple_assignees_review' of gitlab.com:gitlab-org/gitlab-ee into multiple_assignees_review_upstream

Fix issue board avatar counter scss

See merge request !1813

Merge branch 'multiple_assignees_review' of gitlab.com:gitlab-org/gitlab-ee into multiple_assignees_review_upstream

Fix bulk assignees

See merge request !1804

Fix protected branches spec

See merge request !1812

Fix issue dashboard style

See merge request !1809

Fix assign yourself bug

See merge request !1781

Add issue board sidebar specs

See merge request !1790

[Multiple isssue assignees] feature is far behind of the master by this commit I resolve the BE part

Merge branch 'master' of gitlab.com:gitlab-org/gitlab-ee into multiple_assignees_review_upstream[ci skip]

Fix spinach test

See merge request !1780

Fix bug that was causing bulk issue assignment to fail

See merge request !1783

Fix board milestone spec

See merge request !1782

Re-enable ref operations with gitaly after not-found fix

See merge request !1758

[EE] Enable `RSpec/DescribedClass` cop and correct violations

See merge request !1721

Port of "Reject more reserved paths" to EE

See merge request !1778

Fix issue spec

See merge request !1776