initalize default redis connection by redis gem

Author: morgoth

lib/resque.rb

@@ -54,7 +54,7 @@ def redis=(server)
   # create a new one.
   def redis
     return @redis if @redis
-    self.redis = 'localhost:6379'
+    self.redis = Redis.respond_to?(:connect) ? Redis.connect : "localhost:6379"
     self.redis
   end