fix nginx not connecting to php port 9000

nginx/Dockerfile

@@ -5,7 +5,7 @@ MAINTAINER Mahmoud Zalt <mahmoud@zalt.me>
 ADD nginx.conf /etc/nginx/
 ADD laravel.conf /etc/nginx/sites-available/
 
-RUN echo "upstream php-upstream { server php:9000; }" > /etc/nginx/conf.d/upstream.conf
+RUN echo "upstream php-upstream { server php-fpm:9000; }" > /etc/nginx/conf.d/upstream.conf
 
 RUN usermod -u 1000 www-data