This commit adds the module `FromUnion`, which provides the class method
`from_union`. This simplifies the process of selecting data from the
result of a UNION, and reduces the likelihood of making mistakes. As a
result, instead of this:

    union = Gitlab::SQL::Union.new([foo, bar])

    Foo.from("(#{union.to_sql}) #{Foo.table_name}")

We can now write this instead:

    Foo.from_union([foo, bar])

This commit also includes some changes to make this new setup work
properly. For example, a bug in Rails 4
(https://github.com/rails/rails/issues/24193) would break the use of
`from("sub-query-here").includes(:relation)` in certain cases. There was
also a CI query which appeared to repeat a lot of conditions from an
outer query on an inner query, which isn't necessary.

Finally, we include a RuboCop cop to ensure developers use this new
module, instead of using Gitlab::SQL::Union directly.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/51307

Fix grammar (setup to set-up) in code comments, spec, views, etc.

See merge request gitlab-org/gitlab-ce!21699

Add retried jobs to pipeline stages

Closes #50461

See merge request gitlab-org/gitlab-ce!21558

Resolve "Send deployment information in job API"

Closes #50460

See merge request gitlab-org/gitlab-ce!21307

Support Kubernetes RBAC for GitLab Managed Apps for creating new clusters

Closes #29398

See merge request gitlab-org/gitlab-ce!21401

Fixed MR widget unresolved discussions state

See merge request gitlab-org/gitlab-ce!21705

Disable autocomplete for issuable due date field

See merge request gitlab-org/gitlab-ce!21751

Document how to enable/disable Auto DevOps at the instance level

Closes #49820

See merge request gitlab-org/gitlab-ce!21139

Update command-line-commands.md to include an sample taskflow

See merge request gitlab-org/gitlab-ce!21756

Improve docs about CI/CD config `extends`

See merge request gitlab-org/gitlab-ce!21669

CE: Properly implement prepending for Concern

See merge request gitlab-org/gitlab-ce!21444

Relax Danger requirements about changed lines

Closes gitlab-org/release/framework#13

See merge request gitlab-org/gitlab-ce!21739

Update GitLab Shell to v8.3.3

See merge request gitlab-org/gitlab-ce!21750

Cleaned up CI runner administration code

See merge request gitlab-org/gitlab-ce!21741

Remove peek-sidekiq

Closes #51407

See merge request gitlab-org/gitlab-ce!21693

Fix object storage uploads not working with AWS v2

Closes gitlab-workhorse#181

See merge request gitlab-org/gitlab-ce!21731

Fix karma junit result formatter

See merge request gitlab-org/gitlab-ce!21744

Because we were passing query strings as symbols, the fog-aws storage
driver was omitting the uploadId and partNumber query strings
from the signature in multipart uploads. This fix makes AWS and Ceph work with
v2 signatures.

See: https://github.com/fog/fog-aws/blob/v3.0.0/lib/fog/aws/storage.rb#L733

Closes https://gitlab.com/gitlab-org/gitlab-workhorse/issues/181

Fix typo in Danger message

See merge request gitlab-org/gitlab-ce!21746

Prevent premature failure on AutoDevOps Pipeline

Closes gitlab-qa#323

See merge request gitlab-org/gitlab-ce!21709

Add a bullet that the GitLab chart contains the runner

See merge request gitlab-org/gitlab-ce!21733

Adds a note about the case when reset_password is false

See merge request gitlab-org/gitlab-ce!21738

Resolve "Username alignment issue on MR page"

Closes #51412

See merge request gitlab-org/gitlab-ce!21697

In https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/19625 some
changes were introduced that do not meet our abstraction reuse rules.
This commit cleans up some of these changes so the requirements are met.

Most notably, sorting of the runners in Admin::RunnersFinder has been
delegated to Ci::Runner.order_by, similar to how we order data in
models that include the Sortable module. If we need more sort orders in
the future we can include Sortable and have Ci::Runner.order_by call
`super` to delegate to Sortable.order_by.

This relaxes the commit rules regarding the number of changed lines.
Previously we required a detailed description if 20 or more lines were
changed. Starting with this commit we change the rules so Danger only
notifies you about writing a detailed description if:

1. A commit changes more than 3 files
2. The same commit changes more than 30 lines

This should make it easier to do a find replace to fix a typo, without
having to repeat what the subject line already says, while still
reminding developers to write a detailed description for new features
and other larger changes.

Fixes https://gitlab.com/gitlab-org/release/framework/issues/13

docs/ Grammatical Fix workflow.md

See merge request gitlab-org/gitlab-ce!21655

More specificity and clarity for iid field in API documentation.

Closes gitlab-ee#7019

See merge request gitlab-org/gitlab-ce!21490