add i18n for displaying subtitle / cover image

app/views/admin/announcements/_form.html.erb

@@ -69,7 +69,7 @@
 
       <!-- display subtitle -->
       <div class="control-group">
-        <%= f.label :display_subtitle, 'display subtitle', :class => "control-label muted" %>
+        <%= f.label :display_subtitle, t("announcement.display_subtitle"), :class => "control-label muted" %>
         <div class="controls">
           <%= f.check_box :display_subtitle %>
         </div>
@@ -77,7 +77,7 @@
 
       <!-- display img src -->
       <div class="control-group">
-        <%= f.label :display_img, 'display img src', :class => "control-label muted" %>
+        <%= f.label :display_img, t("announcement.display_img"), :class => "control-label muted" %>
         <div class="controls">
           <%= f.check_box :display_img %>
         </div>

config/locales/en.yml

@@ -94,3 +94,5 @@ en:
     is_external_link: Enable External Link
     external_link: External Link
     external_link_hint: "Make sure URL starts with http://"
+    display_subtitle: Display Subtitle
+    display_img: Display Cover Image

config/locales/zh_tw.yml

@@ -98,3 +98,5 @@ zh_tw:
     is_external_link: 連結外部網址
     external_link: 外部連結
     external_link_hint: "確定連結開頭為http://"
+    display_subtitle: 顯示副標題
+    display_img: 顯示圖片