Extend install doc to cover nginx

docs/Installing.asciidoc

@@ -308,12 +308,14 @@ For a local instance setup you can simply execute the script:
 This will automatically setup a local apache http proxy. Read on for more
 detailed setup instructions with all the details.
 
+It is required to run openQA behind an http proxy (apache, nginx, etc..). See the
+*openqa.conf.template* config file in */etc/apache2/vhosts.d* (openSUSE) or
+`/etc/httpd/conf.d` (Fedora) when using apache2 or the config file in
+`/etc/nginx/conf.d` for nginx.
 
 === Apache proxy
 
-It is required to run openQA behind an http proxy (apache, nginx, etc..). See the
-*openqa.conf.template* config file in */etc/apache2/vhosts.d* (openSUSE) or
-`/etc/httpd/conf.d` (Fedora). To make everything work correctly on openSUSE, you
+To make everything work correctly on openSUSE, you
 need to enable the 'headers', 'proxy', 'proxy_http', 'proxy_wstunnel' and 'rewrite'
 modules using the command 'a2enmod'. This is not necessary on Fedora.
 
@@ -336,6 +338,13 @@ required. This will direct all HTTP traffic to openQA.
 cp /etc/apache2/vhosts.d/openqa.conf.template /etc/apache2/vhosts.d/openqa.conf
 --------------------------------------------------------------------------------
 
+=== NGINX proxy
+
+The nginx config is already provided by the openQA RPM package.
+You only need to start the nginx server.
+For openQA you need to set `httpsonly = 0` as described in the TLS/SSL section
+below, if you don't setup nginx for ssl.
+
 === TLS/SSL
 
 By default openQA expects to be run with HTTPS. The `openqa-ssl.conf.template`