Cant set up root for nginx

Hi,

i am in deep problem to deploy my tiny ruby on rails app in ubuntu with
nginx. i have installed nginx. when i browse localhost, its welcoming
me. but while i am trying to browse my blog like localhost/blog , its
showing 404Not found. i have configured nginx.conf file as below

#user nobody;
worker_processes 1;

error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;

pid logs/nginx.pid;

events {
worker_connections 1024;
}

http {
passenger_root
/usr/local/rvm/gems/ruby-1.9.2-p320/gems/passenger-3.0.18;
passenger_ruby /usr/local/rvm/wrappers/ruby-1.9.2-p320/ruby;

include mime.types;
default_type application/octet-stream;
server {
listen 80;
server_name localhost
root /home/sbrc/sukanta/blog/public;
passenger_enabled on;
}
}

Please help me out. i will wait for your response. i have spent 2 days
already to find a solution but nothing is working.please help me. thank
you