Add example nginx config

examples/nginx.conf

+server {
+	listen 80 default_server;
+	listen [::]:80 default_server;
+
+	root /var/www/html;
+
+	# Add index.php to the list if you are using PHP
+	index index.html index.htm index.nginx-debian.html;
+
+	server_name _;
+
+	location / {
+		# Pass request to sms-gateway
+		proxy_pass http://127.0.0.1:4242;
+		# Pass headers
+		proxy_set_header X-Real-IP $remote_addr;
+                proxy_set_header X-Forwarded-Host $host;
+                proxy_set_header X-Forwarded-Port $server_port;
+	}
+}
+