* Add Tombstone model to remember object deletion

* Do not recreate a status if it has been deleted

* Record Tombstone for remote deleted items

Also, only record deleted items from same-host actors

* Clear an user's tombstones when their key change

Fix #9741

Add "agreement: true" to avoid:
> ActiveRecord::RecordInvalid: Validation failed: Agreement must be accepted

Fix #9727

Fix #340

* Add REST API for creating an account

The method is available to apps with a token obtained via the client
credentials grant. It creates a user and account records, as well as
an access token for the app that initiated the request. The user is
unconfirmed, and an e-mail is sent as usual.

The method returns the access token, which the app should save for
later. The REST API is not available to users with unconfirmed
accounts, so the app must be smart to wait for the user to click a
link in their e-mail inbox.

The method is rate-limited by IP to 5 requests per 30 minutes.

* Redirect users back to app from confirmation if they were created with an app

* Add tests

* Return 403 on the method if registrations are not open

* Require agreement param to be true in the API when creating an account

* Add moderation warnings

Replace individual routes for disabling, silencing, and suspending
a user, as well as the report update route, with a unified account
action controller that allows you to select an action (none,
disable, silence, suspend) as well as whether it should generate an
e-mail notification with optional custom text. That notification,
with the optional custom text, is saved as a warning.

Additionally, there are warning presets you can configure to save
time when performing the above.

* Use Account#local_username_and_domain

* Make custom emoji domains case sensitive #9351

* Fixup style in downcase_domain to comply with codeclimate.

* switch if! to unless

* Don't use transactions, operate in batches.

Also revert spurious schema change.

Fix #5578

* fix: change Identity's id column to a bigint

This appears to be the last model created using a 5.0 migration,
where column types defaulted to `integer` rather than `bigint`.

This migration changes the column type to match that of all of the
other ID columns.

* Change user_id column in identities to bigint and fix down-migration

* Add progress indicators to MigrateAccountConversations

* Avoid running expensive query for explain

* Use exec_query instead of execute

* Add locality check to ActivityPub::FetchRemoteAccountService

Fix #8643

Because there are a few places where it is called, it is difficult
to confirm if they all previously checked it for locality. It's better
to make sure within the service.

* Remove faux-remote duplicates of local accounts

* Add silent column to mentions

* Save silent mentions in ActivityPub Create handler and optimize it

Move networking calls out of the database transaction

* Add "limited" visibility level masked as "private" in the API

Unlike DMs, limited statuses are pushed into home feeds. The access
control rules between direct and limited statuses is almost the same,
except for counter and conversation logic

* Ensure silent column is non-null, add spec

* Ensure filters don't check silent mentions for blocks/mutes

As those are "this person is also allowed to see" rather than "this
person is involved", therefore does not warrant filtering

* Clean up code

* Use Status#active_mentions to limit returned mentions

* Fix code style issues

* Use Status#active_mentions in Notification

And remove stream_entry eager-loading from Notification

* Add conversations API

* Add web UI for conversations

* Add test for conversations API

* Add tests for ConversationAccount

* Improve web UI

* Rename ConversationAccount to AccountConversation

* Remove conversations on block and mute

* Change last_status_id to be a denormalization of status_ids

* Add optimistic locking

Fix #8590

* Code quality pass

* Typofix

* Update applications_controller_spec.rb

* Update applications_controller_spec.rb

Fix #8327

Fix #8275

As the batch operation progresses, the statuses_stats table grows,
and the WHERE NOT IN subquery becomes more expensive

* Move status counters to separate table, count replies

* Migration to remove old counter columns from statuses table

* Fix schema file

Adopted from GitLab CE. Generate new migration with:

    rails g post_deployment_migration name_of_migration_here

By default they are run together with db:migrate. To not run them,
the env variable SKIP_POST_DEPLOYMENT_MIGRATIONS must be set

Code by Yorick Peterse <yorickpeterse@gmail.com>, see also:

https://gitlab.com/gitlab-org/gitlab-ce/commit/83c8241160ed48ab066e2c5bd58d0914a745197c

Include a dummy Account class in the migration script containing only the
attributes relevant to the migration in order to not rely as much on the
codebase being in sync with the database schema.

* Add federation relay support

* Add admin UI for managing relays

* Include actor on relay-related activities

* Fix i18n

* Add option to not consider word boundaries when filtering phrases

* Add a few tests for keyword/phrase filtering

* Add keyword filtering

    GET|POST       /api/v1/filters
    GET|PUT|DELETE /api/v1/filters/:id

- Irreversible filters can drop toots from home or notifications
- Other filters can hide toots through the client app
- Filters use a phrase valid in particular contexts, expiration

* Make sure expired filters don't get applied client-side

* Add missing API methods

* Remove "regex filter" from column settings

* Add tests

* Add test for FeedManager

* Add CustomFilter test

* Add UI for managing filters

* Add streaming API event to allow syncing filters

* Fix tests