Add SPAWNERS.md, a list of specific info on spawners

Author: rkdarst

README.md

@@ -24,6 +24,8 @@ This package formerly included WrapSpawner and ProfilesSpawner, which provide me
 
 ## Batch Spawners
 
+For information on the specific spawners, see [SPAWNERS.md](SPAWNERS.md).
+
 ### Overview
 
 This file contains an abstraction layer for batch job queueing systems (`BatchSpawnerBase`), and implements
@@ -82,6 +84,15 @@ to run Jupyter notebooks on an academic supercomputer cluster.
    c.TorqueSpawner.state_exechost_exp = r'int-\1.mesabi.xyz.edu'
    ```
 
+### Security
+
+Unless otherwise stated for a specific spawner, assume that spawners
+*do* evaluate shell environment for users and thus the [security
+requriemnts of JupyterHub security for untrusted
+users](https://jupyterhub.readthedocs.io/en/stable/reference/websecurity.html)
+are not fulfilled.
+
+
 ## Provide different configurations of BatchSpawner
 
 ### Overview

SPAWNERS.md

@@ -0,0 +1,49 @@
+# Notes on specific spawners
+
+## `TorqueSpawner`
+
+Maintainers:
+
+
+## `MoabSpawner`
+
+Subclass of TorqueSpawner
+
+Maintainers:
+
+
+## `SlurmSpawner`
+
+Maintainers: @rkdarst
+
+This spawner enforces the environment if `srun` is used, which is the
+default.  If you *do* want user environment to be used, set
+`req_srun=''`.
+
+
+## `GridengineSpawner`
+
+Maintainers:
+
+
+## `CondorSpawner`
+
+Maintainers:
+
+
+## `LsfSpawner`
+
+Maintainers:
+
+
+# Checklist for making spawners
+
+- Does your spawner read shell environment before starting?
+
+- Does your spawner send SIGTERM to the jupyterhub-singleuser process
+  before SIGKILL?  It should, so that the process can terminate
+  gracefully.  If you don't see the script end (e.g. you can add `echo
+  "terminated gracefully"` to the end of your script and see it), you
+  should check.  PR #75 might help here, ask the poster to finalize
+  it.
+