The permission problem of jupyterhub_config.py

[liudongqing]

After make build and _make up _, the started Jupyterhub doesn't use the configurations in jupyterhub_config.py, it still uses SystemSparwmer.

I found it may be the problem of the access to the config folder. I changed the configuration folder to full access, i.e. 777, only left the cookie secret 700, then it works.