Prepare ru locale maintained (ru)

- set locale to admin/translation-status page
- do redirect to locale from /index.html
- see #2721 for more details

Author: aleksandrilyin

_plugins/translation_status.rb

@@ -8,7 +8,7 @@ module Jekyll
   # Outputs HTML.
   module TranslationStatus
 
-    LANGS = %w[en de es id ja ko pt tr zh_cn zh_tw].freeze
+    LANGS = %w[en de es id ja ko pt ru tr zh_cn zh_tw].freeze
     START_DATE = "2013-04-01"
 
     OK_CHAR      = "✓"

index.html

@@ -11,6 +11,7 @@
         "ja":    "ja",
         "ko":    "ko",
         "pt":    "pt",
+        "ru":    "ru",
         "tr":    "tr",
         "zh-CN": "zh_cn",
         "zh-TW": "zh_tw"