ruby - how to change the result of Time.now? -

i want change results of time.now results time.zone.now

time.now #=> 2015-05-08 14:06:07 +0700 time.zone.now #=> fri, 08 may 2015 02:07:09 cdt -05:00 

should be

time.now #=> fri, 08 may 2015 02:07:09 cdt -05:00 

what should do?