How to change the default nginx page to my web application home page

Even after updating the default server root, the application is not loading by default.

server { listen 80 default_server;

root /var/lib/tomcat7/webapps/web_app_folder/; index index.html index.htm

server_name ip_address;

location / { proxy_pass http://localhost:8080; proxy_set_header X-Forwarded-Host $host; proxy_set_header X-Forwarded-Server $host; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }

i can access using my web applicaiton using the url - http://ip_address/web_app_folder but not with the url - http://ip_address/

Appreciate any help.