add locale rake task

Author: JasonYCHuang

lib/tasks/locale.rake

@@ -0,0 +1,14 @@
+require "react_on_rails/locales_to_js"
+
+namespace :react_on_rails do
+  desc <<-DESC
+Generate i18n javascript files
+This task generates javascript locale files: `translations.js` & `default.js` and places them in
+the "ReactOnRails.configuration.i18n_dir".
+  DESC
+  task locale: :environment do
+    if ReactOnRails.configuration.i18n_dir.present?
+      ReactOnRails::LocalesToJs.new
+    end
+  end
+end