Uninstall Redmine plugin on OpenShift

1. Log into Redmine from SSH
  $ rhc ssh
2. Remove plugin's configuration. (Plugin's name=plugin_name)
  $ RAILS_ENV=production rake db:migrate_plugins PLUGIN={plugin_name} VERSION=0
3. Log out and back into redmine git repo.
4. Remove plugin from source code
  $ git submodule deinit plugins/{plugin_name}
5. Remove submodule info from .gitsubmodule
  $ vi .gitsubmodule
6. Remove plugin's directory
  $ git rm plugins/{plugin_name}
7. Commit & Push it to OpenShift server.
8. Done...