Sorry, I was not sure if your server was setup with EasyEngine or with a custom nginx configuration.
All files in /etc/nginx/common folder are used by EE to set configuration for all your websites depending on the argument used with
ee site create
If you want to add this configuration only for a single website, then just create a configuration file like redirect.conf in /var/www/yourwebsite.com/conf/nginx and copy your location configuration in this file.
Then just reload nginx with
nginx -t && service nginx reload.