nginx rewrite question

[Juergen Gotteswinter]

Hello,

perhaps someone here could help me with the following problem. i got a 
domain justfornow.com which got a wildcard dns entry, and i need to 
redirect this domain to https. but i have to keep the first part of the 
domain, for example:

user calls http://try.justfornow.com nginx rewrites it to 
https://try.justfornow.com
user calls http://anything.justfornow.com nginx keeps the first part and 
rewrites it to https://anything.justfornow.com

thanks :)