Add support for overriding default proxy settings

- If /etc/nginx/proxy.conf exists use that, otherwise use the default

README.md

@@ -143,6 +143,23 @@ You'll need apache2-utils on the machine where you plan to create the htpasswd f
 
 If you need to configure Nginx beyond what is possible using environment variables, you can provide custom configuration files on either a proxy-wide or per-`VIRTUAL_HOST` basis.
 
+#### Overriding default proxy settings
+
+If you want to override the default proxy settings for the nginx container, add a configuration file at `/etc/nginx/proxy.conf`. A file with the default settings would
+look like this:
+
+```Nginx
+# HTTP 1.1 support
+proxy_http_version 1.1;
+proxy_buffering off;
+proxy_set_header Host $http_host;
+proxy_set_header Upgrade $http_upgrade;
+proxy_set_header Connection $proxy_connection;
+proxy_set_header X-Real-IP $remote_addr;
+proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
+```
+
 #### Proxy-wide
 
 To add settings on a proxy-wide basis, add your configuration file under `/etc/nginx/conf.d` using a name ending in `.conf`.

nginx.tmpl

@@ -38,6 +38,9 @@ log_format vhost '$host $remote_addr - $remote_user [$time_local] '
 access_log /proc/self/fd/1 vhost;
 error_log /proc/self/fd/2;
 
+{{ if (exists "/etc/nginx/proxy.conf") }}
+include /etc/nginx/proxy.conf;
+{{ else }}
 # HTTP 1.1 support
 proxy_http_version 1.1;
 proxy_buffering off;
@@ -47,6 +50,7 @@ proxy_set_header Connection $proxy_connection;
 proxy_set_header X-Real-IP $remote_addr;
 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
 proxy_set_header X-Forwarded-Proto $proxy_x_forwarded_proto;
+{{ end }}
 
 server {
 	server_name _; # This is just an invalid value which will never trigger on a real hostname.