Change Domain of Server?

I have an app at site.co but I just bought site.com
How do I set it up where all previous links to site.co redirect to site.com?
ie site.co/username should redirect to site.com/username

The steps required depend on what server you're using but basically you're just changing your server configuration so it responds to the new domain. I use nginx and something like the following would work:
server {
listen 80;
server_name old.example.com;
return 301 http://new.example.com$request_uri;
}
I'm on mobile and can't select to do that in a code block. What this block does is send a 301 which states the content has moved. Anything in search engines or bookmarked wont suddenly stop working