Update nginx.conf (#687)

Changed undefined variable original_uri to request_uri which should use the original request uri. (nginx container won't start otherwise)

Co-authored-by: Julien Nahum <julien@nahum.net>

docker/nginx.conf

@@ -1,6 +1,6 @@
-map $original_uri $api_uri {
+map $request_uri $api_uri {
     ~^/api(/.*$) $1;
-    default $original_uri;
+    default $request_uri;
 }
 
 server {