* Fix misuse of foreign_type

* Fix use of removed "add_template_helper"

* Use response.media_type instead of response.content_type in tests

* Fix CSV export controller test on Rails 6

Rails 6 sets a "filename*" field in the Content-Disposition header to
explicitly encode the filename as UTF-8.

This changes checks the first part of the Content-Disposition header so
it matches in both Rails 5 and Rails 6.

* Fix emoji formatting with Rails 6

* Make emoji output more idiomatic and robust

* Switch from redis-rails gem to built-in Rails redis cache storage

* Bump rubocop from 0.86.0 to 0.88.0

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.86.0 to 0.88.0.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop/compare/v0.86.0...v0.88.0)

Signed-off-by: dependabot[bot] <support@github.com>

* Fix for latest RuboCop

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Yamagishi Kazutoshi <ykzts@desire.sh>

* Add support for special characters in Redis passwords

Fixes #13154

* Refactor

* Add support for separate Redis for cache

CACHE_REDIS_URL to allow using a different Redis server for cache
purposes, with cache-specific configuration such as key eviction

* Fix code style issues

* Set config.cache_store in application.rb

* Set config.cache_store in environments.

* fix code format.