* 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
* Improve webfinger templates and make tests more flexible
* Clean up AS2 representation of actor
* Refactor outbox
* Create activities representation
* Add representations of followers/following collections, do not redirect /users/:username route if format is empty
* Remove unused translations
* ActivityPub endpoint for single statuses, add ActivityPub::TagManager for better
URL/URI generation
* Add ActivityPub::TagManager#to
* Represent all attachments as Document instead of Image/Video specifically
(Because for remote ones we may not know for sure)
Add mentions and hashtags representation to AP notes
* Add AP-resolvable hashtag URIs
* Use ActiveModelSerializers for ActivityPub
* Clean up unused translations
* Separate route for object and activity
* Adjust cc/to matrices
* Add to/cc to activities, ensure announce activity embeds target status and
not the wrapper status, add "id" to all collections
* Add request spec for host meta route returning xml
* Add routing spec for xrd routes
* Update well-known routes
* Move webfinger and host-meta actions to their own controllers
