* Remove docker guide and put it in docs repo

* Move tasks to docs repo

* Move requirements to contributing doc

* Move advice about tagged releases to docs repo

* Move local domain and host config to docs repo

* Link to related tech

These were being skipped with `xit`, but we also just added the `unused` task to
the CI server, and it will be caught there. That seems good enough for this,
instead of requiring a full keys check on every local spec suite run.

* Add spec for media controller

* Add MediaAttachment.attached scope

* Simplify methods in media controller

Also improve efficiency of the mastodon:maintenance:add_static_avatars task

This change includes:

- Improve the spec coverage for incoming request to the webfinger action
- For requests without an accept header (ie, what a browser might look like),
  return a JSON response.
- For requests with an explicit format of xml or json, return that format.
- For requests using an accept header, return that format.

Also adds failing spec showing webfinger does not return xml, which covers the
issue described in: https://github.com/tootsuite/mastodon/issues/1983

* Add `required: true` option to foreign column

* Fixes NoMethodError

```
> Favourite.new.valid?
NoMethodError: undefined method `reblog?' for nil:NilClass
```

Sync text for toot form

Un utiliser mal expérimenté pourrait comprendre "retirer les erreurs".
Ici il s'agit d'une suppression pure et simple, pas une épuration/nettoyage.

clear would be translated "remove" instead of "cleaning" Cleaning can be unterstood "keep but clean"

This is necessary for boosting long posts on small screens - see this post for video: https://slime.global/@masklayer/102308

* Open sidekiq and pghero admin pages in new tabs

* Add missing comma

This introduces a new per-user preference called
"Auto-play animated GIFs", which is enabled by default. When a
user disables this setting, gifs in toots become click-to-play.

Previews of animated gifs were changed to display the video play
button so that users can distinguish them from regular images.

This setting also affects account avatars in the detailed account
view, which was changed to use the same hover-to-play mechanism
that is used for animated avatars in timelines.

Fixes #1652

Without setting it, exim will reject the mail with a message like:
rejected EHLO from [10.20.0.1]: syntactically invalid argument(s): {}

* Allow using an SMTP server without authentication (e.g Postfix relay on the same host) by setting SMTP_LOGIN and SMTP_AUTH_METHOD to 'none'

* Add note in .env.production.sample about SMTP settings for servers where no auth is required

* Assume that SMTP_LOGIN and SMTP_PASSWORD will be blank if we set SMTP_AUTH_METHOD to none

* Add mask-icon (#1572)

* use updated svg logo for mask-icon

* update portuguese translation

added the missing fields and improved the translation

* pt translations fix

* improve last translation commit

* fix damn quotes

* add pt_br to index.jsx

* add pt-BR to import index.jsx

* add pt-BR to mastodon.jsx

* add pt-BR to settings_helper.rb

* add pt-BR to application.rb

* order alphabetically pt.jsx

* create pt-BR.jsx

* Create devise.pt-BR.yml

* language improvements to devise.pt.yml

* created doorkeeper.pt-BR.yml

* fixes to doorkeeper.pt.yml

* create pt-BR.yml

* improvements to pt.yml

* Create simple_form.pt-BR.yml

* Improvements to simple_form.pt.yml

* improvements to pt.yml

* Create hr.jsx

Start of Croatian translation

* Update settings_helper.rb

* Update application.rb

* Update application.rb

* Update index.jsx

* Remove overflow because it blocks scrolling on mobile safari.

* Add “-webkit-overflow-scrolling: touch;” to enable smooth scroll on mobile safari and other webkit browsers.

* Use radio buttons in user setting page.

Because select tags with long text are not fit in the width of mobile devices.

* Add flex property to fit labels to devise width.

* Change font size of select.

It causes auto zooming on mobile safari.

* Rubocop link for Sublime Text

* Fix rubocop links

* Link to gh issues page from contributing doc

* reduce unneed query when post without attachements.

This commit reduce following query:

```
 MediaAttachment Load (0.9ms)  SELECT "media_attachments".* FROM "media_attachments" WHERE "media_attachments"."status
_id" IS NULL AND 1=0 ORDER BY id asc
```

* fixed for more simple changes.

* Fix #1870 - Strip control characters out of strings in AtomSerializer

* Adjust according to comment by @alpaca-tc

* Add language detection via WhatLanguage and (de)serialization of it through Atom

* Fix default language in ProcessFeedService

* Re-add newline before 'react-rails' Gem to fix groupings

Fixes Code Climate issue

* Basic onboarding modal that's shown to users once

* Lay out pages 2 through 5, add images, style modals (#1509)

* Lay out pages 2 through 5

Added images and laid out pages 2 through 5 in the jsx file. SCSS will
come, still working on just seeing if this works at all.

* Fix jsx errors, add images to modal pages, style modal pages

* Add animations to onboarding pager changes, improve wording and styling

* Finishing touches on the onboarding

* Add missing propTypes

* Update wording

* update Dockerfile: latest nodejs LTS

* also update imagemagick

* Rename admin.domain_block to admin.domain_blocks in prep for i18n improvement

* Use implicit controller/action path for i18n in admin/domain_blocks

* Add DomainBlock#accounts has_many

* Avoid i18n health warning for `en` locale by using symbol scope with :count

* Remove unused i18n key: plaintext_secret_html

* Remove unused i18n key two_factor_auth.warning

* Remove final will_paginate i18n keys

* Remove unused key two_factor_auth.recovery_codes

* Remove unused key: admin.reports.comment.none

* Remove unused reports. i18n namespace (moved to admin.reports)

* Ignore keys from locales which override activemodel and activerecord errors

* Revert "Remove unused key: admin.reports.comment.none"

This reverts commit 350ef2685f.

* Update i18n key reference to match moved location

* Add missing `en` keys to i18n

* Tell i18n-tasks to ignore missing attributes that dont need overwriting

* Add i18n-tasks unused to travis

The <link rel="mentioned" /> tag refers to accounts by href. So we were
matching the DB by the url attribute, and falling back to HTTP look-up.
However, GS and Mastodon use profile URLs as URIs, too, and the match
for that was missing. This could potentially alleviate some extra network
requests