correct locale helper so it falls back to english message format if mf is missing

lib/javascripts/moment_locale/ko.js

@@ -2,7 +2,7 @@
 // language : korean (ko)
 // author : Kyungwook, Park : https://github.com/kyungw00k
 
-require('../moment').lang('ko', {
+moment.lang('ko', {
     months : "1월_2월_3월_4월_5월_6월_7월_8월_9월_10월_11월_12월".split("_"),
     monthsShort : "1월_2월_3월_4월_5월_6월_7월_8월_9월_10월_11월_12월".split("_"),
     weekdays : "일요일_월요일_화요일_수요일_목요일_금요일_토요일".split("_"),

lib/js_locale_helper.rb

@@ -50,7 +50,11 @@ module JsLocaleHelper
     formats = message_formats.map{|k,v| k.inspect << " : " << compile_message_format(locale_str ,v)}.join(" , ")
 
     result = "MessageFormat = {locale: {}};\n"
-    result << File.read(Rails.root + "lib/javascripts/locale/#{locale_str}.js") << "\n"
+
+    filename = Rails.root + "lib/javascripts/locale/#{locale_str}.js"
+    filename = Rails.root + "lib/javascripts/locale/en.js" unless File.exists?(filename)
+
+    result << File.read(filename) << "\n"
 
     result << "I18n.messageFormat = (function(formats){
       var f = formats;