Some anti-crash fixes

setup/heroku/nginx.conf

@@ -0,0 +1,15 @@
+location / {
+    # try to serve file directly, fallback to rewrite
+    try_files $uri @rewriteapp;
+}
+
+location @rewriteapp {
+    # rewrite all to index.php
+    rewrite ^(.*)$ /index.php/$1 last;
+}
+
+location ~ ^/index\.php(/|$) {
+    try_files @heroku-fcgi @heroku-fcgi;
+    # ensure that /index.php isn't accessible directly, but only through a rewrite
+    internal;
+}