Nginx rewrite: replace - with /

I set up ghost blogging platform. It doesn't allow to insert «/» signs in article links, but I want them to appear in my links, so I want them to be fixed with nginx rewrites.

The link in a browser looks like this:

http://blog.site.com/stuff-life/

And I want it to be like this:

http://blog.site.com/stuff/life/

It goes without saying that it should be applied for a number of links starting from "stuff-*", not for one.

I found this, but it's way too complicated for me:

http://nginx.org/en/docs/http/ngx_http_rewrite_module.html

My config looks like this:

server {
listen 80;
server_name blog.site.com;
access_log /var/log/nginx/ghost.log;
error_log /var/log/nginx/ghost.error.log;
    location / {
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header HOST $http_host;
        proxy_set_header X-NginX-Proxy true;

        proxy_pass http://127.0.0.1:2368;
        proxy_redirect off;
        }
}

So how I do a rewrite in my case? Thanks.

Update.

Now I try to do it this way:

server {
listen 80;
server_name somesite.com;
access_log /var/log/nginx/ghost.log;
error_log /var/log/nginx/ghost.error.log;
location / {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header HOST $http_host;
    proxy_set_header X-NginX-Proxy true;

    proxy_pass http://127.0.0.1:2368;
    proxy_redirect off;
}


location /stuff- {
    rewrite ^/stuff-(.*) http://$server_name/stuff/$1 permanent;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header HOST $http_host;
    proxy_set_header X-NginX-Proxy true;

    proxy_pass http://127.0.0.1:2368;
    proxy_redirect off;
}


}

And it looks like nginx is passing rewrited links to ghost. And I get 404 page.