如何使用Whenever gem强制rake任务在开发环境下运行

I'm using Whenever gem to run a rake task. When I run rake task it runs under development environment, but when it runs on a scheduled time it refers to a production environment. How can I force to run a scheduled rake task under development environment. As I understand I'll have to use RAILS_ENV variable, but can't figure out where to put it. I think, it has nothing to do with Whenever gem here.I'm using Whenever gem to run a rake task. When