Use dedicated relative_url.rb initializer

in order to have it the same way like in omnibus

.gitignore

@@ -23,6 +23,7 @@ config/gitlab.yml
 config/gitlab_ci.yml
 config/initializers/rack_attack.rb
 config/initializers/smtp_settings.rb
+config/initializers/relative_url.rb
 config/resque.yml
 config/unicorn.rb
 config/secrets.yml

config/application.rb

@@ -54,14 +54,6 @@ module Gitlab
 
     config.action_view.sanitized_allowed_protocols = %w(smb)
 
-    # Relative URL support
-    # WARNING: We recommend using an FQDN to host GitLab in a root path instead
-    # of using a relative URL.
-    # Documentation: http://doc.gitlab.com/ce/install/relative_url.html
-    # Uncomment and customize the following line to run in a non-root path
-    #
-    # config.relative_url_root = "/gitlab"
-
     config.middleware.use Rack::Attack
 
     # Allow access to GitLab API from other domains

config/initializers/relative_url.rb.sample

@@ -0,0 +1,10 @@
+# Relative URL support
+# WARNING: We recommend using an FQDN to host GitLab in a root path instead
+# of using a relative URL.
+# Documentation: http://doc.gitlab.com/ce/install/relative_url.html
+# Copy this file to relative_url.rb and customize it to run in a non-root path
+#
+
+Rails.application.configure do
+  config.relative_url_root = "/gitlab"
+end

doc/install/relative_url.md

@@ -25,7 +25,7 @@ that points to your GitLab instance.
 The TL;DR list of configuration files that you need to change in order to
 serve GitLab under a relative URL is:
 
-- `/home/git/gitlab/config/application.rb`
+- `/home/git/gitlab/config/initializers/relative_url.rb`
 - `/home/git/gitlab/config/gitlab.yml`
 - `/home/git/gitlab/config/unicorn.rb`
 - `/home/git/gitlab-shell/config.yml`
@@ -66,8 +66,14 @@ Make sure to follow all steps below:
     sudo service gitlab stop
     ```
 
-1.  Edit `/home/git/gitlab/config/application.rb` and uncomment/change the
-    following line:
+1.  Create `/home/git/gitlab/config/initializers/relative_url.rb`
+
+    ```shell
+    cp /home/git/gitlab/config/initializers/relative_url.rb.sample \
+       /home/git/gitlab/config/initializers/relative_url.rb
+    ```
+
+    and change the following line:
 
     ```ruby
     config.relative_url_root = "/gitlab"
@@ -119,8 +125,12 @@ Make sure to follow all steps below:
 
 ### Disable relative URL in GitLab
 
-To disable the relative URL, follow the same steps as above and set up the
-GitLab URL to one that doesn't contain a relative path.
+To disable the relative URL:
+
+1.  Remove `/home/git/gitlab/config/initializers/relative_url.rb`
+
+1.  Follow the same as above starting from 2. and set up the
+    GitLab URL to one that doesn't contain a relative path.
 
 [omnibus-rel]: http://doc.gitlab.com/omnibus/settings/configuration.html#configuring-a-relative-url-for-gitlab "How to setup relative URL in Omnibus GitLab"
 [restart gitlab]: ../administration/restart_gitlab.md#installations-from-source "How to restart GitLab"