Summary

Following the directions at https://docs.gitlab.com/omnibus/gitlab-mattermost/ in the Running GitLab Mattermost on its own server section. No options for gitlab_rails['enable'] found.

Steps to reproduce

Edit gitlab.rb and add gitlab_rails['enable'] = false causes gitlab-ctl reconfigure to fail out:

Starting Chef Client, version 12.12.15
resolving cookbooks for run list: ["gitlab"]
Synchronizing Cookbooks:
  - package (0.0.0)
  - runit (0.14.2)
  - gitlab (0.0.1)
Installing Cookbook Gems:
Compiling Cookbooks...
Recipe: gitlab::default
  * directory[/etc/gitlab] action create (up to date)
/sbin/init: unrecognized option '--version'
-.mount                                                                             loaded active mounted   /
  Converging 159 resources

Running handlers:
Running handlers complete
Chef Client failed. 0 resources updated in 05 seconds

1. Version number
   $ apt-cache policy gitlab-ce
   gitlab-ce:
   Installed: 8.12.7-ce.0

2. Steps to reproduce your issue
   Enter gitlab_rails['enable'] = false to /etc/gitlab/gitlab.rb and run sudo gitlab-ctl reconfigure