WIP: Allow for a custom gitlab.rb
Towards #26 (closed) we need a mechanism to configure the omnibus-gitlab in the docker image with a gitlab.rb that specifies that an optional feature (eg. mattermost) should be enabled.
In order to do this safely we introduce new
#run methods to GitLab::QA::Docker::Gitlab, retaining
#start in terms of
This allows for us to specify a sequence of actions like
create; configure(custom_config); run; reconfigure, an example of this is currently in the Test::Omnibus::Image scenario.