Declare Ukrainian

Closes: #345

app/assets/javascripts/components/containers/mastodon.jsx

@@ -41,6 +41,7 @@ import es from 'react-intl/locale-data/es';
 import fr from 'react-intl/locale-data/fr';
 import pt from 'react-intl/locale-data/pt';
 import hu from 'react-intl/locale-data/hu';
+import uk from 'react-intl/locale-data/uk';
 import getMessagesForLocale from '../locales';
 
 const store = configureStore();
@@ -49,7 +50,7 @@ const browserHistory = useRouterHistory(createBrowserHistory)({
   basename: '/web'
 });
 
-addLocaleData([...en, ...de, ...es, ...fr, ...pt, ...hu]);
+addLocaleData([...en, ...de, ...es, ...fr, ...pt, ...hu, ...uk]);
 
 const Mastodon = React.createClass({
 

app/helpers/settings_helper.rb

@@ -8,6 +8,7 @@ module SettingsHelper
     pt: 'Português',
     fr: 'Français',
     hu: 'Magyar',
+    uk: 'Українська',
   }.freeze
 
   def human_locale(locale)