Add Dutch translation (nl) (#1682)

* Dutch language files for Ruby code

 * Created RoR translation ymls:
   * config/locales/devise.nl.yml
   * config/locales/doorkeeper.nl.yml
   * config/locales/nl.yml
   * config/locales/simple_form.nl.yml

 * Modified RoR config and helper
   * app/helpers/settings_helper.rb
   * config/application.rb

* Dutch language javascript locale

 * Created javascript locale files:
   * app/assets/javascripts/components/locales/index.jsx
   * app/assets/javascripts/components/locales/nl.jsx

 * Reference the newly created locale files:
   * app/assets/javascripts/components/containers/mastodon.jsx

* Fix syntax error in locale file (nl)

* Fix missing translate in js locale (nl)

* Convert all ruby Dutch locale (nl) file to utf8

Fix yml conversion issues.

* Fix duplicated key in devise.nl.yml

* Fix indentation error in doorkeeper.nl.yml

4 files changed, 73 insertions, 0 deletions

diff --git a/app/assets/javascripts/components/containers/mastodon.jsx b/app/assets/javascripts/components/containers/mastodon.jsx
index b9086de42..5cd727822 100644
--- a/app/assets/javascripts/components/containers/mastodon.jsx
+++ b/app/assets/javascripts/components/containers/mastodon.jsx
@@ -48,6 +48,7 @@ import fr from 'react-intl/locale-data/fr';
 import hu from 'react-intl/locale-data/hu';
 import ja from 'react-intl/locale-data/ja';
 import pt from 'react-intl/locale-data/pt';
+import nl from 'react-intl/locale-data/nl';
 import no from 'react-intl/locale-data/no';
 import ru from 'react-intl/locale-data/ru';
 import uk from 'react-intl/locale-data/uk';
@@ -76,6 +77,7 @@ addLocaleData([
   ...hu,
   ...ja,
   ...pt,
+  ...nl,
   ...no,
   ...ru,
   ...uk,
diff --git a/app/assets/javascripts/components/locales/index.jsx b/app/assets/javascripts/components/locales/index.jsx
index f14568a3d..7525022b1 100644
--- a/app/assets/javascripts/components/locales/index.jsx
+++ b/app/assets/javascripts/components/locales/index.jsx
@@ -3,6 +3,7 @@ import de from './de';
 import es from './es';
 import hu from './hu';
 import fr from './fr';
+import nl from './nl';
 import no from './no';
 import pt from './pt';
 import uk from './uk';
@@ -19,6 +20,7 @@ const locales = {
   es,
   hu,
   fr,
+  nl,
   no,
   pt,
   uk,
diff --git a/app/assets/javascripts/components/locales/nl.jsx b/app/assets/javascripts/components/locales/nl.jsx
new file mode 100644
index 000000000..cc80854fc
--- /dev/null
+++ b/app/assets/javascripts/components/locales/nl.jsx
@@ -0,0 +1,68 @@
+const nl = {
+  "column_back_button.label": "terug",
+  "lightbox.close": "Sluiten",
+  "loading_indicator.label": "Laden...",
+  "status.mention": "Vermeld @{name}",
+  "status.delete": "Verwijder",
+  "status.reply": "Reageer",
+  "status.reblog": "Boost",
+  "status.favourite": "Favoriet",
+  "status.reblogged_by": "{name} boostte",
+  "status.sensitive_warning": "Gevoelige inhoud",
+  "status.sensitive_toggle": "Klik om te zien",
+  "video_player.toggle_sound": "Geluid omschakelen",
+  "account.mention": "Vermeld @{name}",
+  "account.edit_profile": "Bewerk profiel",
+  "account.unblock": "Deblokkeer @{name}",
+  "account.unfollow": "Ontvolg",
+  "account.block": "Blokkeer @{name}",
+  "account.follow": "Volg",
+  "account.posts": "Berichten",
+  "account.follows": "Volgt",
+  "account.followers": "Volgers",
+  "account.follows_you": "Volgt jou",
+  "account.requested": "Wacht op goedkeuring",
+  "getting_started.heading": "Beginnen",
+  "getting_started.about_addressing": "Je kunt mensen volgen als je hun gebruikersnaam en het domein van hun server kent, door het e-mailachtige adres in het zoekscherm in te voeren.",
+  "getting_started.about_shortcuts": "Als de gezochte gebruiker op hetzelfde domein zit als jijzelf, is invoeren van de gebruikersnaam genoeg. Dat geldt ook als je mensen in de statussen wilt vermelden.",
+  "getting_started.open_source_notice": "Mastodon is open source software. Je kunt bijdragen of problemen melden op GitHub via {github}. {apps}.",
+  "column.home": "Thuis",
+  "column.community": "Lokale tijdlijn",
+  "column.public": "Federatietijdlijn",
+  "column.notifications": "Meldingen",
+  "tabs_bar.compose": "Schrijven",
+  "tabs_bar.home": "Thuis",
+  "tabs_bar.mentions": "Vermeldingen",
+  "tabs_bar.public": "Federatietijdlijn",
+  "tabs_bar.notifications": "Meldingen",
+  "compose_form.placeholder": "Waar ben je mee bezig?",
+  "compose_form.publish": "Toot",
+  "compose_form.sensitive": "Markeer media als gevoelig",
+  "compose_form.spoiler": "Verberg tekst achter waarschuwing",
+  "compose_form.private": "Mark als privé",
+  "compose_form.privacy_disclaimer": "Je besloten status wordt afgeleverd aan vermelde gebruikers op  {domains}. Vertrouw je {domainsCount, plural, one {that server} andere {those servers}}? Privé plaatsen werkt alleen op Mastodon servers. Als {domains} {domainsCount, plural, een {is not a Mastodon instance} andere {are not Mastodon instances}}, dan wordt er geen indicatie gegeven dat he bericht besloten is, waardoor het kan worden geboost of op andere manier zichtbaar worden voor niet bedoelde lezers.",
+  "compose_form.unlisted": "Niet tonen op openbare tijdlijnen",
+  "navigation_bar.edit_profile": "Bewerk profiel",
+  "navigation_bar.preferences": "Voorkeuren",
+  "navigation_bar.community_timeline": "Lokale tijdlijn",
+  "navigation_bar.public_timeline": "Federatietijdlijn",
+  "navigation_bar.logout": "Uitloggen",
+  "reply_indicator.cancel": "Annuleren",
+  "search.placeholder": "Zoeken",
+  "search.account": "Account",
+  "search.hashtag": "Hashtag",
+  "upload_button.label": "Toevoegen media",
+  "upload_form.undo": "Ongedaan maken",
+  "notification.follow": "{name} volgde jou",
+  "notification.favourite": "{name} markeerde je status als favoriet",
+  "notification.reblog": "{name} boostte je status",
+  "notification.mention": "{name} vermeldde jou",
+  "notifications.column_settings.alert": "Desktopmeldingen",
+  "notifications.column_settings.show": "Tonen in kolom",
+  "notifications.column_settings.follow": "Nieuwe volgers:",
+  "notifications.column_settings.favourite": "Favoriten:",
+  "notifications.column_settings.mention": "Vermeldingen:",
+  "notifications.column_settings.reblog": "Boosts:",
+};
+
+export default nl;
diff --git a/app/helpers/settings_helper.rb b/app/helpers/settings_helper.rb
index 212f88c39..c6ffe184e 100644
--- a/app/helpers/settings_helper.rb
+++ b/app/helpers/settings_helper.rb
@@ -8,6 +8,7 @@ module SettingsHelper
     eo: 'Esperanto',
     fr: 'Français',
     hu: 'Magyar',
+    nl: 'Nederlands',
     no: 'Norsk',
     pt: 'Português',
     fi: 'Suomi',