new_contents: # Configuration file for jupyterhub.
  
  import os
  import subprocess
  import os
  import errno
  import stat
  
  c = get_config()
  pwd = os.path.dirname(__file__)
  
  c.JupyterHub.spawner_class = 'cassinyspawner.SwarmSpawner'
  
  c.JupyterHub.ip = '0.0.0.0'
  c.JupyterHub.hub_ip = '0.0.0.0'
  
  c.JupyterHub.cleanup_servers = False
  
  # First pulls can be really slow, so let's give it a big timeout
  c.SwarmSpawner.start_timeout = 60 * 5
  
  c.SwarmSpawner.jupyterhub_service_name = 'jupyterhub'
  
  c.SwarmSpawner.networks = ["jupyterhub"]
  
  notebook_dir = os.environ.get('NOTEBOOK_DIR') or '/home/jovyan/work'
  c.SwarmSpawner.notebook_dir = notebook_dir
  
  mounts = [{'type' : 'volume',
             'source' : 'jupyterhub-user-{username}',
             'target' : notebook_dir}]
  
  c.SwarmSpawner.container_spec = {
      # The command to run inside the service
      'command' : '/usr/local/bin/start-singleuser.sh', #(string or list)
      'Image' : 'YourImage',
      'mounts' : mounts
      }
  
  c.SwarmSpawner.resource_spec = {
                  'cpu_limit' : 1000, # (int) – CPU limit in units of 10^9 CPU shares.
                  'mem_limit' : int(512 * 1e6), # (int) – Memory limit in Bytes.
                  'cpu_reservation' : 1000, # (int) – CPU reservation in units of 10^9 CPU shares.
                  'mem_reservation' : int(512 * 1e6), # (int) – Memory reservation in Bytes
                  }
subject: add examples