Update Rails to 4.0.1

cf. http://techracho.bpsinc.jp/baba/2013_11_02/14645

Please notice that rails' `order.order` sequence meaning was changed (fixed).

BTW, I noticed that tag_list query is (and was) like

```
SELECT tags.*, taggings.tags_count AS count FROM `tags` JOIN (SELECT taggings.tag_id, 
COUNT(taggings.tag_id) AS tags_count FROM `taggings` INNER JOIN nodes ON nodes.id = 
taggings.taggable_id AND nodes.type = 'Graph' WHERE (taggings.taggable_type = 'Node' AND 
taggings.context = 'tags') AND (taggings.taggable_id IN(NULL)) GROUP BY taggings.tag_id HAVING
COUNT(taggings.tag_id) > 0) AS taggings ON taggings.tag_id = tags.id
ORDER BY name ASC, count DESC LIMIT 400
```

See the last line. So, ORDER BY count is just useless. What I wanted to do here is like ORDER BY count DESC LIMIT 400, then, ORDER BY name ASC. How to do it? => I gave up. removed ORDER BY count DESC