Remove duplicate in Rails 2 & 3 initializers

init.rb

@@ -0,0 +1,5 @@
+require 'delayed_job'
+
+config.after_initialize do
+  Delayed::Worker.guess_backend
+end

lib/delayed/railtie.rb

@@ -4,14 +4,7 @@
 module Delayed
   class Railtie < Rails::Railtie
     initializer :after_initialize do
-      Delayed::Worker.backend ||= if defined?(ActiveRecord)
-        :active_record
-      elsif defined?(MongoMapper)
-        :mongo_mapper
-      else
-        Delayed::Worker.logger.warn "Could not decide on a backend, defaulting to active_record"
-        :active_record
-      end
+      Delayed::Worker.guess_backend
     end
   end
 end

lib/delayed/worker.rb

@@ -32,6 +32,17 @@ def self.backend=(backend)
       @@backend = backend
       silence_warnings { ::Delayed.const_set(:Job, backend) }
     end
+
+    def self.guess_backend
+      self.backend ||= if defined?(ActiveRecord)
+        :active_record
+      elsif defined?(MongoMapper)
+        :mongo_mapper
+      else
+        logger.warn "Could not decide on a backend, defaulting to active_record"
+        :active_record
+      end
+    end
 
     def initialize(options={})
       @quiet = options[:quiet]