The old approach was to require the runner connection. This did
not work anymore with Zeitwerk in Rails 6. @sebastian.serth and I
moved the Connection class in `lib` into the ActiveRecord class
`Runner`. This will also work with future changes like specific
error classes. Furthermore the config was fixed and simplified.
Co-authored-by: Sebastian Serth <Sebastian.Serth@hpi.de>
Many functions in submission_controller.rb still are very long and have
a high complexity. Because the logic for handling execution of
submissions will probably move elsewhere (when switching to
ActionCable), this is fine for now.
