small updates to the docs

docs/howto/auth/ldap.rst

@@ -0,0 +1,46 @@
+.. _howto/auth/ldap:
+
+=============================
+Using LDAP for authentication
+=============================
+
+`LDAP <https://en.wikipedia.org/wiki/Lightweight_Directory_Access_Protocol>`_
+is an open and widely-used protocol for authentication.
+
+The `LDAPAuthenticator's documentation <https://github.com/jupyterhub/ldapauthenticator#required-configuration>`_
+lists the various configuration options you can set for LDAPAuthenticator. You can set them
+in TLJH with the following pattern:
+
+.. code-block:: bash
+
+   sudo -E tljh-config set auth.<authenticator-name>.<config-option-name> <config-option-value>
+
+When the documentation asks you to set ``LDAPAuthenticator.server_address`` to some
+value, you can do that with the following command:
+
+.. code-block:: bash
+
+   sudo -E tljh-config set auth.LDAPAuthenticator.server_address = 'my-ldap-server'
+
+Enabling the authenticator
+==========================
+
+For LDAPAuthenticator, the fully qualified name is ``ldapauthenticator.LDAPAuthenticator``.
+This is the same name that the `documentation asks <https://github.com/jupyterhub/ldapauthenticator#usage>`_
+you to set ``c.JupyterHub.authenticator_class`` to.
+
+For LDAPAuthenticator, this would be:
+
+.. code-block:: bash
+
+   sudo -E tljh-config set auth.type ldapauthenticator.LDAPAuthenticator
+
+Once enabled, you need to reload JupyterHub for the config to take effect.
+
+.. code-block:: bash
+
+   sudo -E tljh-config reload
+
+Try logging in a separate incognito window to check if your configuration works. This
+lets you preserve your terminal in case there were errors. If there are
+errors, :ref:`troubleshooting/logs` should help you debug them.