improved configuration utility

config/initializers/action_mailer.rb

@@ -1,3 +1,3 @@
-YAML.load_file(Rails.root.join('config', 'action_mailer.yml'))[Rails.env].each do |key, value|
+CodeOcean::Config.new(:action_mailer).read.each do |key, value|
   CodeOcean::Application.config.action_mailer.send(:"#{key}=", value.respond_to?(:symbolize_keys) ? value.symbolize_keys : value)
 end

config/initializers/sendmail.rb

@@ -1,3 +1,3 @@
 if CodeOcean::Application.config.action_mailer.delivery_method == :sendmail
-  CodeOcean::Application.config.action_mailer.sendmail_settings = CodeOcean::Config.new('sendmail').read
+  CodeOcean::Application.config.action_mailer.sendmail_settings = CodeOcean::Config.new(:sendmail).read
 end

config/initializers/smtp.rb

@@ -1,3 +1,3 @@
 if CodeOcean::Application.config.action_mailer.delivery_method == :smtp
-  CodeOcean::Application.config.action_mailer.sendmail_settings = CodeOcean::Config.new('smtp').read
+  CodeOcean::Application.config.action_mailer.sendmail_settings = CodeOcean::Config.new(:smtp).read
 end