Fix link, filename and crosslink to omnibus docs.

doc/README.md

@@ -56,7 +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.
+- [Environment Variables](administration/environment_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.

doc/administration/enviroment_variables.md → doc/administration/environment_variables.md

@@ -39,7 +39,12 @@ GITLAB_DATABASE_PASSWORD |
 GITLAB_DATABASE_HOST | localhost
 GITLAB_DATABASE_PORT | 5432
 
-## Other variables
+## Adding more variables
 
 We welcome merge requests to make more settings configurable via variables.
 Please stick to the naming scheme "GITLAB_#{name 1_settings.rb in upper case}".
+
+## Omnibus configuration
+
+It's possible to preconfigure the GitLab image by adding the environment variable: `GITLAB_OMNIBUS_CONFIG` to docker run command.
+For more information see the ['preconfigure-docker-container' section in the Omnibus documentation](http://doc.gitlab.com/omnibus/docker/#preconfigure-docker-container).