[jupyterhub] add debugging

jupyterhub/base/jupyter_notebook_config.py

@@ -2,3 +2,4 @@ c.NotebookApp.allow_root = True
 c.NotebookApp.terminado_settings = {"shell_command": ["/bin/bash", "-l"]}
 c.MultiKernelManager.default_kernel_name = "default"
 c.NotebookApp.notebook_dir = "/root"
+c.Session.debug = True