how to enable gzip on dotcloud

put nginx.conf at the root of application.
cat nginx.conf
gzip on;
gzip_http_version 1.0;
gzip_types text/plain application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript font/truetype;
gzip_disable "MSIE [1-6]\.";

now restart nginx.
dotcloud run app.www sudo /etc/init.d/nginx restart

enjoy it.