Use environment variables to configure GitLab.

config/initializers/1_settings.rb

@@ -144,7 +144,7 @@ Settings.gitlab['default_projects_limit'] ||= 10
 Settings.gitlab['default_branch_protection'] ||= 2
 Settings.gitlab['default_can_create_group'] = true if Settings.gitlab['default_can_create_group'].nil?
 Settings.gitlab['default_theme'] = Gitlab::Themes::APPLICATION_DEFAULT if Settings.gitlab['default_theme'].nil?
-Settings.gitlab['host']       ||= 'localhost'
+Settings.gitlab['host']       ||= ENV['GITLAB_HOST'] || 'localhost'
 Settings.gitlab['ssh_host']   ||= Settings.gitlab.host
 Settings.gitlab['https']        = false if Settings.gitlab['https'].nil?
 Settings.gitlab['port']       ||= Settings.gitlab.https ? 443 : 80

doc/README.md

@@ -56,6 +56,7 @@
 - [Issue closing](customization/issue_closing.md) Customize how to close an issue from commit messages.
 - [Libravatar](customization/libravatar.md) Use Libravatar for user avatars.
 - [Log system](logs/logs.md) Log system.
+- [Environmental Variables](administration/environmental_variables.md) to configure GitLab.
 - [Operations](operations/README.md) Keeping GitLab up and running
 - [Raketasks](raketasks/README.md) Backups, maintenance, automatic web hook setup and the importing of projects.
 - [Security](security/README.md) Learn what you can do to further secure your GitLab instance.