use explicit autoloads rather than from paths

lib/postal.rb

@@ -0,0 +1,42 @@
+module Postal
+
+  extend ActiveSupport::Autoload
+
+  eager_autoload do
+    autoload :AppLogger
+    autoload :BounceMessage
+    autoload :Config
+    autoload :Countries
+    autoload :DKIMHeader
+    autoload :Error
+    autoload :FastServer
+    autoload :Helpers
+    autoload :HTTP
+    autoload :HTTPSender
+    autoload :Job
+    autoload :LetsEncrypt
+    autoload :MessageDB
+    autoload :MessageInspection
+    autoload :MessageParser
+    autoload :MessageRequeuer
+    autoload :QueryString
+    autoload :RabbitMQ
+    autoload :ReplySeparator
+    autoload :RspecHelpers
+    autoload :SendResult
+    autoload :Sender
+    autoload :SMTPServer
+    autoload :SpamCheck
+    autoload :UserCreator
+    autoload :Version
+    autoload :Worker
+  end
+
+  def self.eager_load!
+    super
+    Postal::MessageDB.eager_load!
+    Postal::FastServer.eager_load!
+    Postal::SMTPServer.eager_load!
+  end
+
+end