Delegate initialization to Runner::Strategy

config/application.rb

@@ -49,6 +49,9 @@ module CodeOcean
     config.after_initialize do
       # Initialize the counters according to the db
       Prometheus::Controller.initialize_metrics
+
+      # Initialize the runner environment
+      Runner.strategy_class.initialize_environment
     end
   end
 end

config/initializers/docker.rb

@@ -1,5 +0,0 @@
-# frozen_string_literal: true
-
-require 'docker_client'
-
-DockerClient.initialize_environment unless Rails.env.test? && `which docker`.blank?