config for mailer previews

config/environments/development.rb

@@ -41,6 +41,8 @@ Metamaps::Application.configure do
   # Print deprecation notices to the Rails logger
   config.active_support.deprecation = :log
 
+  config.action_mailer.preview_path = '/vagrant/spec/mailers/previews'
+
   # Expands the lines which load the assets
   config.assets.debug = true
 end