update staging gems

Gemfile

@@ -53,3 +53,6 @@ group :test do
   gem 'webmock'
 end
 
+group :production do
+  gem 'rails_12factor'
+end

Gemfile.lock

@@ -164,6 +164,11 @@ GEM
       bundler (>= 1.3.0, < 2.0)
       railties (= 4.1.0)
       sprockets-rails (~> 2.0)
+    rails_12factor (0.0.2)
+      rails_serve_static_assets
+      rails_stdout_logging
+    rails_serve_static_assets (0.0.2)
+    rails_stdout_logging (0.0.3)
     railties (4.1.0)
       actionpack (= 4.1.0)
       activesupport (= 4.1.0)
@@ -270,6 +275,7 @@ DEPENDENCIES
   pry-rails
   rack-timeout
   rails (>= 4.0.3)
+  rails_12factor
   recipient_interceptor
   rspec-rails (>= 2.14)
   sass-rails (~> 4.0.2)

config/environments/staging.rb

@@ -5,5 +5,5 @@ Mail.register_interceptor RecipientInterceptor.new(ENV['EMAIL_RECIPIENTS'])
 Vidpush::Application.configure do
   # ...
 
-  config.action_mailer.default_url_options = { host: 'staging.vidpush.com' }
+  config.action_mailer.default_url_options = { host: 'propel-vidpush-staging.herokuapp.com' }
 end