Remove idle culler example

Has been moved to its own repo.

See jupyterhub/the-littlest-jupyterhub#559
for more info

examples/cull-idle/README.md

@@ -1,41 +1,4 @@
-# `cull-idle` Example
+# idle-culler example
 
-The `cull_idle_servers.py` file provides a script to cull and shut down idle
-single-user notebook servers. This script is used when `cull-idle` is run as
-a Service or when it is run manually as a standalone script.
-
-
-## Configure `cull-idle` to run as a Hub-Managed Service
-
-In `jupyterhub_config.py`, add the following dictionary for the `cull-idle`
-Service to the `c.JupyterHub.services` list:
-
-```python
-c.JupyterHub.services = [
-    {
-        'name': 'cull-idle',
-        'admin': True,
-        'command': [sys.executable, 'cull_idle_servers.py', '--timeout=3600'],
-    }
-]
-```
-
-where:
-
-- `'admin': True` indicates that the Service has 'admin' permissions, and
-- `'command'` indicates that the Service will be managed by the Hub.
-
-## Run `cull-idle` manually as a standalone script
-
-This will run `cull-idle` manually. `cull-idle` can be run as a standalone
-script anywhere with access to the Hub, and will periodically check for idle
-servers and shut them down via the Hub's REST API. In order to shutdown the
-servers, the token given to cull-idle must have admin privileges.
-
-Generate an API token and store it in the `JUPYTERHUB_API_TOKEN` environment
-variable. Run `cull_idle_servers.py` manually. 
-
-```bash
-    export JUPYTERHUB_API_TOKEN=$(jupyterhub token)
-    python3 cull_idle_servers.py [--timeout=900] [--url=http://127.0.0.1:8081/hub/api]
-```
+The idle culler has been moved to its own repository at
+[jupyterhub/jupyterhub-idle-culler](https://github.com/jupyterhub/jupyterhub-idle-culler).