How to host multiple rails site on Nginx

User following code in Nginx.conf file.. and paste into that file
#vim /etc/nginx/nginx.conf


http {
include       /etc/nginx/mime.types;
default_type  application/octet-stream;
access_log  /var/log/nginx/access.log  main;
sendfile        on;

upstream mongrel_cluster_example1 {
server 127.0.0.1:8000;
server 127.0.0.1:8001;
server 127.0.0.1:8002;
}

upstream mongrel_cluster_example2 {
server 127.0.0.1:3000;
server 127.0.0.1:3001;
server 127.0.0.1:3002;
}

# Load config files from the /etc/nginx/conf.d directory
include /etc/nginx/conf.d/*.conf;

server {
listen       80;
server_name  example1.com example2.net;
client_max_body_size 120M;

set $myroot /var/www/html;
if ($host ~* example1\.com$) {
set $myroot /home/example1/public;
}

if ($host ~* example2\.net$) {
set $myroot /home/example2/public;
}

root $myroot;

location ~* ^/(images|stylesheets|javascripts).+\.(html|jpg|jpeg|gif|png|ico|css|zip|tgz|gz|rar|bz2|doc|xls|exe|pdf|ppt|txt|tar|mid|midi|wav|bmp|rtf|js)$
{
root $myroot;
}

location / {

if ($host ~* example1\.com$) {
proxy_pass      http://mongrel_cluster_example1;
} #if check for domain qa.teenangel ends here

if ($host ~* example2\.net$) {
root /home/rail_project/myproject/public;
proxy_pass      http://mongrel_cluster_example2;

} #if check for domain ends here

}

}

}