Increase nginx max body size

Otherwise large thumbnails can't be uploaded

nginx/generate-config

@@ -54,6 +54,7 @@ events {
 http {
 	include /etc/nginx/mime.types;
 	resolver 127.0.0.11 valid=10s;
+	client_max_body_size 20M;
 $SSL_CONF
 	server {
 		listen 80;