include_root_in_json set to false is not working in rails 4

I kept below code in my model file, self.include_root_in_json = false

First, I tried to get json with following command, SearchTag.find(1).to_json, and got

     SearchTag Load (0.1ms)  SELECT `search_tags`.* FROM `search_tags` WHERE `search_tags`.`id` = 1 LIMIT 1
      => "{\"search_tag\":{\"id\":1,\"name\":\"test\",\"created_at\":\"2015-04-01T00:00:00.000Z\",\"updated_at\":\"2015-04-01T00:00:00.000Z\"}}"

Then, I added self.include_root_in_json = false in search_tag.rb file, reloaded the console and ran same command and received,

    SearchTag Load (0.2ms)  SELECT `search_tags`.* FROM `search_tags` WHERE `search_tags`.`id` = 1 LIMIT 1
      => "{\"id\":1,\"name\":\"test\",\"created_at\":\"2015-04-01T00:00:00.000Z\",\"updated_at\":\"2015-04-01T00:00:00.000Z\"}"

Which is desired result, but, I don't get this result in browser... I always get {"search_tags":["test","test1"]}