When querying the deployments of an environment the query Rails produces
will be along the lines of the following:

    SELECT *
    FROM deployments
    WHERE environment_id = X

For queries such as this (or queries that use this as their base and add
more conditions) there is no meaningful index that can be used as long
as deployments.project_id is not part of a WHERE clause.

To work around this we change that "has_many :deployments" relation to
always add a "WHERE project_id = X" condition. This means that queries
filtering deployments can make better use of the existing indexes. For
example, when filtering by deployments.iid this will result in the
following query:

    SELECT *
    FROM deployments
    WHERE environment_id = X
    AND project_id = Y
    AND iid = Z

This means PostgreSQL can use the existing index on
(project_id, environment_id, iid) instead of having to use a different
index (or none at all) and having to scan over a large amount of data.

Query plan wise this means that instead of this query and plan:

    EXPLAIN (BUFFERS, ANALYZE)
    SELECT deployments.*
    FROM deployments
    WHERE deployments.environment_id = 5
    AND deployments.iid = 225;

    Index Scan using index_deployments_on_project_id_and_iid on deployments  (cost=0.42..14465.75 rows=1 width=117) (actual time=6.394..38.048 rows=1 loops=1)
      Index Cond: (iid = 225)
      Filter: (environment_id = 5)
      Rows Removed by Filter: 839
      Buffers: shared hit=4534
    Planning time: 0.076 ms
    Execution time: 38.073 ms

We produce the following query and plan:

    EXPLAIN (BUFFERS, ANALYZE)
    SELECT deployments.*
    FROM deployments
    WHERE deployments.environment_id = 5
    AND deployments.iid = 225
    AND deployments.project_id = 1292351;

    Index Scan using index_deployments_on_project_id_and_iid on deployments  (cost=0.42..4.45 rows=1 width=117) (actual time=0.018..0.018 rows=1 loops=1)
      Index Cond: ((project_id = 1292351) AND (iid = 225))
      Filter: (environment_id = 5)
      Buffers: shared hit=4
    Planning time: 0.088 ms
    Execution time: 0.039 ms

On GitLab.com these changes result in a (roughly) 11x improvement in SQL
timings for the CI environment status endpoint.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/36877

AutoDevOps banner hidden on explicit CI config

Closes #37652

See merge request !14207

Fix: GPG tmp dir removal race condition

Ignore any errors when removing the tmp directory, as we may run into a
race condition:
The `gpg-agent` agent process may clean up some files as well while
`FileUtils.remove_entry` is iterating the directory and removing all its
contained files and directories recursively, which could raise an error.

Closes #36998

See merge request !14194

Replace the 'profile/active_tab.feature' spinach test with an rspec analog

See merge request !14239

Extends the helper method to no show the banner as soon as the project
has a `.gitlab-ci.yml` file on the default branch.

Fixes gitlab-org/gitlab-ce#37652

Merge branch '37629-lazy-image-loading-breaks-notification-mails-for-an-added-screenshot' into 'master'

Resolve "Lazy image loading breaks notification mails for an added screenshot"

Closes #37629

See merge request !14161

Docs for automatically inherit the milestone and labels of the issue

See merge request !14223

Fix the Doorkeeper.optional_scopes issue triggered by !13314

Closes #37753

See merge request !14219

Allow all AutoDevOps banners to be disabled

Closes #37653

See merge request !14218

Add usage ping for Auto DevOps

Closes #37648

See merge request !14162

Add help text to runner edit page that tags should be separated by commas.

Closes #37405

See merge request !14224

Resolve "New issue from failed build no longer links to failed build"

Closes #36907

See merge request !13790

Resolve "Move `lib/ci` to `lib/gitlab/ci`"

Closes #5836

See merge request !14078

Remove db/migrate/20170828135939_migrate_user_external_mail_data.rb

See merge request !14240

Update mysql_to_postgresql.md to deprecate these docs in favor of PGLoader

See merge request !14238

This file is a duplicate of a post-deploy migration and appears to have
been left in by mistake.

Looping through the Users table in a foreground migration would've been
a bad idea.

[ci skip]

Resolve "Image onion skin + swipe does not work anymore"

Closes #37730 and #37732

See merge request !14215

fix CI

fix CI

Revert "Merge branch 'revert-f2421b2b' into 'master'"

See merge request !14190

Fix Auto DevOps quick start guide

Closes #37768

See merge request !14230

Decrease Perceived Complexity threshold to 15

See merge request !14160

Decrease Cyclomatic Complexity threshold to 13

See merge request !14152

Migrate Git::CommitStats to Gitaly

Closes gitaly#519

See merge request !14077

Add developer documentation about working with sent emails and previews

See merge request !14227