Fix table_exists? to be Rails5 compatible

Closes #45107

See merge request gitlab-org/gitlab-ce!19418

Unify spec/lib/banzai/filter/image_lazy_load_filter_spec.rb

See merge request gitlab-org/gitlab-ce!19836

Move Gitaly RPCs to mandatory

Closes gitaly#217, gitaly#389, gitaly#390, gitaly#220, gitaly#376, and gitaly#354

See merge request gitlab-org/gitlab-ce!19759

Resolve "Reference to master still cached"

Closes #47851

See merge request gitlab-org/gitlab-ce!19827

Bring `rake postgresql_md5_hash` to CE

Closes gitlab-ee#6419

See merge request gitlab-org/gitlab-ce!19830

[Rails5] Fix snippets_finder arel queries

Closes #47832

See merge request gitlab-org/gitlab-ce!19796

Backport EE .flayignore lines to CE

See merge request gitlab-org/gitlab-ce!19829

Deny repository disk access in development and test

See merge request gitlab-org/gitlab-ce!19716

Fix flakey time-sensitive user comment on issue test

See merge request gitlab-org/gitlab-ce!19786

Fix fields for author & assignee in MR API docs

Closes #42445

See merge request gitlab-org/gitlab-ce!19798

Remove incorrect CI doc re: PowerShell

Closes #40164

See merge request gitlab-org/gitlab-ce!19622

Bring changes from EE for lib/system_check/simple_executor.rb

See merge request gitlab-org/gitlab-ce!19782

Invalidate cache with project details when repository is updated

Closes #33733

See merge request gitlab-org/gitlab-ce!19774

Add assignee lists to tiers table in docs

See merge request gitlab-org/gitlab-ce!19756

Fix shoulda-matchers in Rails 5

Closes #47639

See merge request gitlab-org/gitlab-ce!19749

Wrap YAML error in Web IDE pipelines panel

Closes #47755

See merge request gitlab-org/gitlab-ce!19736

For master->maintainer permission rename

Closes https://gitlab.com/gitlab-org/gitaly/issues/217

Closes https://gitlab.com/gitlab-org/gitaly/issues/217

enable CommonMark as the default

See merge request gitlab-org/gitlab-ce!19331

Closes: https://gitlab.com/gitlab-org/gitaly/issues/389

Closes https://gitlab.com/gitlab-org/gitaly/issues/390

Closes: https://gitlab.com/gitlab-org/gitaly/issues/220

Migration: https://gitlab.com/gitlab-org/gitaly/issues/220

Migration: https://gitlab.com/gitlab-org/gitaly/issues/220

Fixed six broken links in README.md

See merge request gitlab-org/gitlab-ce!19797

Rails5 ActionController::ParameterMissing: param is missing or the value is…

Closes #47805

See merge request gitlab-org/gitlab-ce!19763

Rails5 fix no implicit conversion of Hash into String

Closes #47835

See merge request gitlab-org/gitlab-ce!19792

Rails5 fix stack level too deep

Closes #47804

See merge request gitlab-org/gitlab-ce!19762

Use data_source_exists? where possible instead of table_exists? in order to be Rails5 compatible

Closes #42445.

Closes #40164.