Add nginx parameters to pass the scheme.

README.md

@@ -13,3 +13,14 @@ Licence of the files depends on their locations.
 Unless noted otherwise:
 - all files under the `src` directory are licenced under the [GNU General Public License version 2](https://www.gnu.org/licenses/gpl-2.0.html) or any later version (GPLv2+).
 - all files under the `static` directory are under the [Creative Commons Attribution-ShareAlike 4.0](https://creativecommons.org/licenses/by-sa/4.0/).
+
+# Proxy
+When behind a proxy, the proxy must pass the Host header, and set the X-Scheme header.
+Exemple with nginx :
+```
+location / {
+  proxy_set_header Host $http_host;
+  proxy_set_header X-Scheme $scheme;
+  proxy_pass http://localhost:8080;
+}
+```