In `arel 7.0` (`7.1.4` version is used for rails5) there were introduced
some changes that break our code in the `User#manageable_groups` method.

The problem is that `arel_table[:id].in(Arel::Nodes::SqlLiteral)` generates
wrong `IN ()` construction. The selection for `IN` is missing:

=> "\"namespaces\".\"id\" IN (0)"

That caused such spec errors for the `rails5` branch:

```
4) User groups with child groups #manageable_groups does not include duplicates if a membership was added for the subgroup
    Failure/Error: expect(user.manageable_groups).to contain_exactly(group, subgroup)

      expected collection contained:  [#<Group id:232 @group29>, #<Group id:234 @group29/group30>]
      actual collection contained:    []
      the missing elements were:      [#<Group id:232 @group29>, #<Group id:234 @group29/group30>]
    # ./spec/models/user_spec.rb:699:in `block (5 levels) in <top (required)>'
    # ./spec/spec_helper.rb:188:in `block (2 levels) in <top (required)>'
    # /var/lib/gems/2.3.0/gems/rspec-retry-0.4.6/lib/rspec/retry.rb:112:in `block in run'
    # /var/lib/gems/2.3.0/gems/rspec-retry-0.4.6/lib/rspec/retry.rb:101:in `loop'
    # /var/lib/gems/2.3.0/gems/rspec-retry-0.4.6/lib/rspec/retry.rb:101:in `run'
    # /var/lib/gems/2.3.0/gems/rspec-retry-0.4.6/lib/rspec_ext/rspec_ext.rb:12:in `run_with_retry'
    # /var/lib/gems/2.3.0/gems/rspec-retry-0.4.6/lib/rspec/retry.rb:30:in `block (2 levels) in setup'
```

This commit changes `User#manageable_groups` in the way to drop the usage of
`Arel::Nodes::SqlLiteral` and adds usage of raw SQL query.
This change should be updated when we're migrated to Rails 5.2 because arel
was fixed in `9.0.0` (which is used in Rails 5.2).

Fix finding wiki file when Gitaly is enabled

Closes gitaly#1126

See merge request gitlab-org/gitlab-ce!18317

[CE Backport] Propagate broadcast messages to secondaries

See merge request gitlab-org/gitlab-ce!18324

Limit dropdown toggle width for protected branches / tags

See merge request gitlab-org/gitlab-ce!18212

Document example for sprintf without escaping

See merge request gitlab-org/gitlab-ce!16712

Add i18n and update specs for UnresolvedDiscussions vue component

See merge request gitlab-org/gitlab-ce!17866

Vertical misalignment of login box header

Closes #41748

See merge request gitlab-org/gitlab-ce!16275

Add possibility to filter Karma spec files by path

Closes #40899

See merge request gitlab-org/gitlab-ce!16102

Move TimeTrackingEstimateOnlyPane vue component

See merge request gitlab-org/gitlab-ce!18318

[Rails5] Update Event#subclass_from_attributes method

See merge request gitlab-org/gitlab-ce!18312

Link Monitor docs to the front page

Closes #45006

See merge request gitlab-org/gitlab-ce!18314

Fixes gitaly#1126

Resolve "tree/master shows incorrect CI build status"

Closes #44541

See merge request gitlab-org/gitlab-ce!17995

Replace vue resource with axios for pipeline details page

See merge request gitlab-org/gitlab-ce!18285

Client implementation for InfoAttributes

See merge request gitlab-org/gitlab-ce!18261

Resolve "Illustration for the case where the job has finished and the log was erased"

Closes #45159

See merge request gitlab-org/gitlab-ce!18253

Clients can now request the attributes from `$GIT_DIR/info/attributes`
through Gitaly. The Gitaly migration is described in gitlab-org/gitaly#1082.

The parser algorithm was implemented in a way it could handle both file
contents or a File handle, and both were already tested.

Other than that, using the boy scout rule, I've removed a class,
InfoAttributes, as it was delegating everything to the parser and
therefor wasn't really needed in my opinion.

Resolve "Clean outdated flaky specs from the flaky specs report"

Closes #37721

See merge request gitlab-org/gitlab-ce!18196

Replace the `project/issues/milestones.feature` spinach test with an rspec analog

See merge request gitlab-org/gitlab-ce!18300

Replace the `project/commits/branches.feature` spinach test with an rspec analog

See merge request gitlab-org/gitlab-ce!18302

Resolve "When editing a comment in an issue, the preview mode is toggled in the main textarea"

Closes #44697

See merge request gitlab-org/gitlab-ce!18303

In Rails 5.0 the `ActiveRecord::Inheritance::subclass_from_attributes`
method was updated.
Now it calls the `find_sti_class` method [1] which is overriden in the `Event`
model and returns needed class (`Event` vs `PushEvent`).

[1]: https://github.com/rails/rails/blob/5-0-stable/activerecord/lib/active_record/inheritance.rb#L209

This commit fixes the errors like
```
143) User#contributed_projects doesn't include IDs for unrelated projects
      Failure/Error: action = attrs.with_indifferent_access[inheritance_column].to_i

      NoMethodError:
        undefined method `with_indifferent_access' for nil:NilClass
      # ./app/models/event.rb:118:in `subclass_from_attributes'
```
which are raised on the `RAILS5=1 rspec ...` command.

Branch with a commit detection defaults to Gitaly

See merge request gitlab-org/gitlab-ce!18304

Tag with a commit detection defaults to Gitaly

See merge request gitlab-org/gitlab-ce!18305

Fix file-specific variables collection item option

Closes gitlab-ee#5444

See merge request gitlab-org/gitlab-ce!18307

Fixed markdown preview in IDE not working for new files

See merge request gitlab-org/gitlab-ce!18287

[Rails5] Fix admin/application_settings_controller

See merge request gitlab-org/gitlab-ce!18275

By default this was an OPT_IN RPC, and now graduates to OPT_OUT as the
acceptance testing was successful in:
gitaly#1009

This follows the conventions of our [migration
process](https://gitlab.com/gitlab-org/gitaly/blob/master/doc/MIGRATION_PROCESS.md)

By default this was an OPT_IN RPC, and now graduates to OPT_OUT as the
acceptance testing was successful in:
https://gitlab.com/gitlab-org/gitaly/issues/1008

This follows the conventions of our [migration
process](https://gitlab.com/gitlab-org/gitaly/blob/master/doc/MIGRATION_PROCESS.md)