Move customizing-hostnames documentation

[ci skip]

docs/nginx.md

@@ -131,36 +131,14 @@ chown dokku:dokku /home/dokku/myapp/nginx.conf.d/upload.conf
 service nginx reload
 ```
 
-## Customizing hostnames
-
-Applications typically have the following structure for their hostname:
-
-```
-scheme://subdomain.domain.tld
-```
-
-The `subdomain` is inferred from the pushed application name, while the `domain.tld` is set during initial configuration and stored in the `$DOKKU_ROOT/VHOST` file. It can then be modified with `dokku domains:set-global`. This value is used as a default TLD for all applications on a host.
-
-If a FQDN such as `other.tld` is used as the application name, the default `$DOKKU_ROOT/VHOST` will be ignored and the resulting vhost URL for that application will be `other.tld`. The exception to this rule being that if the FQDN has the same ending as the default vhost (such as `subdomain.domain.tld`), then the entire FQDN will be treated as a subdomain. The application will therefore be deployed at `subdomain.domain.tld.domain.tld`.
-
-You can optionally override this in a plugin by implementing the `nginx-hostname` plugin trigger. For example, you can reverse the subdomain with the following sample `nginx-hostname` plugin trigger:
-
-```shell
-#!/usr/bin/env bash
-set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
-
-APP="$1"; SUBDOMAIN="$2"; VHOST="$3"
-
-NEW_SUBDOMAIN=`echo $SUBDOMAIN | rev`
-echo "$NEW_SUBDOMAIN.$VHOST"
-```
-
-If the `nginx-hostname` has no output, the normal hostname algorithm will be executed.
-
-### Domains plugin
+## Domains plugin
 
 See the [domain-configuration documentation](/dokku/deployment/domain-configuration/).
 
+## Customizing hostnames
+
+See the [customizing hostnames documentation](/dokku/deployment/domain-configuration/#customizing-hostnames).
+
 ## Disabling VHOSTS
 
 See the [disabling vhosts documentation](/dokku/deployment/domain-configuration/#disabling-vhosts).