I tried what Julian said and got this message:
ln: failed to create symbolic link `./sites-available': File exists
And this error when running nginx -t:
nginx: [crit] pread() "/etc/nginx/sites-enabled/sites-available" failed (21: Is a directory)
nginx: configuration file /etc/nginx/nginx.conf test failed
I tried all three of the methods listed in the documentation, but no dice. Any tips? I just did the regular digital ocean setup for dummies, but I can't get past the reverse proxy step even after reading every single mention of "nginx" on the forum. I feel like a grade-A moron 
By the way, the site is at http://nutritionask.com:4567.
When I use the nginx.conf file I paste the server block at the end and get this error:
2014/05/16 15:33:47 [emerg] 30304#0: "server" directive is not allowed here in /etc/nginx/n ginx.conf:97
nginx: configuration file /etc/nginx/nginx.conf test failed
Here is what I pasted. How do you make it all cool looking with the black background btw?
server {
listen 0.0.0.0:80;
server_name nutritionask.com;
location / {
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_set_header X-NginX-Proxy true;
proxy_pass http://127.0.0.1:4567/;
proxy_redirect off;
# Socket.IO Support
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
}
}