Fix bootstrap warning

[thalessr]

ActionController::RoutingError (No route matches [GET] "/apple-touch-icon.png"): actionpack (4.1.1) lib/action_dispatch/middleware/debug_exceptions.rb:21:in call' actionpack (4.1.1) lib/action_dispatch/middleware/show_exceptions.rb:30:incall' railties (4.1.1) lib/rails/rack/logger.rb:38:in call_app' railties (4.1.1) lib/rails/rack/logger.rb:20:inblock in call' activesupport (4.1.1) lib/active_support/tagged_logging.rb:68:in block in tagged' activesupport (4.1.1) lib/active_support/tagged_logging.rb:26:intagged' activesupport (4.1.1) lib/active_support/tagged_logging.rb:68:in tagged' railties (4.1.1) lib/rails/rack/logger.rb:20:incall' actionpack (4.1.1) lib/action_dispatch/middleware/request_id.rb:21:in call' rack (1.5.2) lib/rack/methodoverride.rb:21:incall' rack (1.5.2) lib/rack/runtime.rb:17:in call' activesupport (4.1.1) lib/active_support/cache/strategy/local_cache_middleware.rb:26:incall' rack (1.5.2) lib/rack/lock.rb:17:in call' actionpack (4.1.1) lib/action_dispatch/middleware/static.rb:64:incall' rack (1.5.2) lib/rack/sendfile.rb:112:in call' railties (4.1.1) lib/rails/engine.rb:514:incall' railties (4.1.1) lib/rails/application.rb:144:in call' rack (1.5.2) lib/rack/lock.rb:17:incall' rack (1.5.2) lib/rack/content_length.rb:14:in call' rack (1.5.2) lib/rack/handler/webrick.rb:60:inservice' /Users/thalesribeiro/.rbenv/versions/2.1.2/lib/ruby/2.1.0/webrick/httpserver.rb:138:in service' /Users/thalesribeiro/.rbenv/versions/2.1.2/lib/ruby/2.1.0/webrick/httpserver.rb:94:inrun' /Users/thalesribeiro/.rbenv/versions/2.1.2/lib/ruby/2.1.0/webrick/server.rb:295:in `block in start_thread'