rails 4 locale switcher not working on heroku -

i have bilingual rails 4 application deployed in heroku - russian & english. worked until 1 day locale switcher broke no reason. it's working fine on development , production version - when point language link shows normal link 'localhost:3000/en' or 'localhost:3000/ru' param. in heroku shows 'abarskaya.com/%7b:locale=>' instead of 'abarskaya.com/ru' or 'abarskaya.com/en'. strange didn't change anything. here's application controller

class applicationcontroller < actioncontroller::base   protect_from_forgery   before_filter :set_locale    protected   def set_locale     i18n.locale = params[:locale] || session[:locale] || i18n.default_locale   end    # ensure locale persists   def default_url_options(options={})     logger.debug "default_url_options passed options: #{options.inspect}\n"     { locale: i18n.locale }   end end 

and route.rb file is:

scope "(:locale)", locale: /ru|en/   'about' => 'home#about', :as => 'about'   'services' => 'home#services', :as => 'services'   'contacts' => 'home#contacts', :as => 'contacts' end  root :to => 'home#index' '/:locale' => 'home#index' 

here's switcher in shared/_header.html.erb partial (i'm using rails_bootstrap_navbar gem)

<li class="dropdown visible-desktop">   <a href="#" class="dropdown-toggle" data-toggle="dropdown"><%= image_tag(:en == locale ? 'us-flag.png' : 'ru-flag.png') %> <b class="caret"></b></a>   <ul class="dropdown-menu">     <li class="nav-header"><%= t(:language) %></li>     <li class="divider"></li>     <%= menu_item 'english', locale: 'en' %>     <%= menu_item 'Русский', locale: 'ru' %>   </ul> </li> 

any appreciated. anyway i'm pretty sure have dumb mistake somewhere. ;)