Correctly set the host headers

This was causing the links in the API responses to be rendered e.g. without the
correct port, so later ones in the pagination would fail.

See wger-project/flutter#911

Author: rolandgeider

config/nginx.conf

@@ -8,10 +8,10 @@ server {
 
     location / {
         proxy_pass http://wger;
-        proxy_set_header Host $host;
+        proxy_set_header Host $http_host;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
-        proxy_set_header X-Forwarded-Proto $http_x_forwarded_proto;
-        proxy_set_header X-Forwarded-Host $host:$server_port;
+        proxy_set_header X-Forwarded-Proto $scheme;
+        proxy_set_header X-Forwarded-Host $http_host;
         proxy_redirect off;
     }