GitLab Change Host

On you GitLab Server , how to change you host name?

We can see this is on gitlab default host name.

external_url 'http://gitlab.example.com'

and then , how to change ?

$sudo vim /etc/gitlab/gitlab.rb

We can find and change to you server_ip or domain 

 external_url 'http://you server_ip or domain'

and then to commit 

$sudo gitlab-ctl reconfigure 

and 

$sudo gitlab-ctl restart 

Reload web , we can see link to change you setting.