Fixing failing master:
https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/116776474

Fix bug causing not all emails to show up in commit email selectbox

Closes #54045

See merge request gitlab-org/gitlab-ce!23079

Fix styling of snippet and commit discussion comments

Closes #53918

See merge request gitlab-org/gitlab-ce!23035

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/54045

Fix vertical line alignment in discussion & diff border-radius

Closes #53975

See merge request gitlab-org/gitlab-ce!23075

Add white background to commit diff comments

See merge request gitlab-org/gitlab-ce!23078

Fix Git protocol v2 e2e test

Closes gitlab-org/quality/staging#16

See merge request gitlab-org/gitlab-ce!23067

Update proofreader.md

See merge request gitlab-org/gitlab-ce!20752

Updates pipeline code to use gitlab-ui

See merge request gitlab-org/gitlab-ce!22999

Remove references to `Factory`

Fix collapsed files not fully fully expanding

Closes #53866

See merge request gitlab-org/gitlab-ce!23019

Disable updating appearance of filter tokens for special values

Closes #53636

See merge request gitlab-org/gitlab-ce!22865

Add a new markup languages section

See merge request gitlab-org/gitlab-ce!22921

Show navigation line separator when instance metrics is disabled

See merge request gitlab-org/gitlab-ce!22940

Add missing slash in frontend testing guide

See merge request gitlab-org/gitlab-ce!23027

Switch to Rails 5

Closes #14286 and #48991

See merge request gitlab-org/gitlab-ce!21492

Move cloud-native-image to the post-test stage

Closes charts/gitlab#897

See merge request gitlab-org/gitlab-ce!22942

Bump GitLab Workhorse to 7.1.1

See merge request gitlab-org/gitlab-ce!23053

Bump `binding_of_caller` gem version to 0.8.0

See merge request gitlab-org/gitlab-ce!23040

Merge branch '54002-activity-feed-missing-padding-in-event-note-when-a-branch-is-deleted' into 'master'

Resolve "Activity Feed - Missing padding in event note when a branch is deleted"

Closes #54002

See merge request gitlab-org/gitlab-ce!23038

This version now supports redis[s]:// URL schemes.

In Rails 5 all models by default inherit from ApplicationRecord.

We want to run CI with rails 4 for a short-term (until we are sure that
we will ship with rails 5). The problem is that rails 4 can not handle
rails 5 schema.rb properly - specifically `t.index` directive can not
handle multiple indexes on the same column.

Because combination of rails 4 + rails 5 schema will be used
only in CI for a short-term, we can just ignore these incompatibility
failures. This patch adds `rails5` helper for specs.

* add_index replaced with t.index
* intiger(size 8) replaced with bigint

* similar to rails 5 it assures that index length is set for blob
  columns also in rails 4
* it also ignores multiple definitions of indexes for mysql, for some
  tables we define multiple indexes on the same set of columns, but with
  different parameters (opclasses, where), these are not supported by
  mysql adapter so the second definition of index is skipped

CI jobs will be triggered both with rails 4 and 5
to make sure we keep backward compatibility if it turns out
we have to switch back to rails 4.

Rails 4 jobs are not allowed to fail for now, these jobs will be
removed in a follow-up MR next cycle.