Still trying to resolve www/non-www issue with my app

I’ve been trying for a while to figure out how to get www.ourapp.com to redirect to ourapp.com. I found this Stackoverflow post, which seems very clear, but so far I haven’t been able to make it work: http://stackoverflow.com/questions/7947030/nginx-no-www-to-www-and-www-to-no-www

It’s a Rails app, and I recently realized there’s an nginx.conf file in the config directory that’s executed as part of the deploy script; previously I had been sshing into the server directory and modifying the file in etc/nginx/sites-enabled, but didn’t realize it was getting written over every time I deployed.

However, even modifying the file there still it hasn’t having any effect. Nginx.conf currently looks like this (as does the version on the server now, obviously):

upstream unicorn {
  server unix:/tmp/unicorn.streamfeed.sock fail_timeout=0;
}

server {
  server_name www.streamfeed.com;
  return 301 http://streamfeed.com$request_uri;
}

server {
  listen 80 default deferred;
  server_name streamfeed.com;
  root /home/deployer/apps/streamfeed/current/public;

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;
  }

  try_files $uri/index.html $uri @unicorn;
  location @unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://unicorn;
  }

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;
}

I’ve also tried the version suggested for https in that SO post (which some other people suggest for http as well), using rewrite ^(.*) http://domain.com$1 permanent, and that doesn’t do anything either - I can have two different sessions open on our site at streamfeed.com and www.streamfeed.com. I’ve been banging my head against the wall on this for a long time at this point…obviously i’m missing something, but I don’t know what it is - can anyone help?