Add NativeAuth as an optional authenticator

docs/howto/auth/nativeauth.rst

@@ -0,0 +1,38 @@
+.. _howto/auth/nativeauth:
+
+==================================================
+Users can signup and create username and password
+==================================================
+
+The **Native Authenticator** lets users signup for creating a new username 
+and password.
+When they signup, they won't be able to login until they are authorized by an 
+admin. Users that are characterized as admin have to signup as well, but they  
+will be authorized automatically.
+
+
+Enabling the authenticator
+==========================
+
+#. Enable the authenticator and reload config to apply the configuration:
+
+   sudo tljh-config set auth.type nativeauthenticator.NativeAuthenticator
+   sudo tljh-config reload
+
+
+Allowing all users to be authorized after signup
+================================================
+
+By default, all users created on signup don't have authorization to login. 
+If you wish to allow **any** user to access
+the JupyterHub just after the signup, run the following command:
+
+.. code-block:: bash
+
+   tljh-config set auth.NativeAuthenticator.open_signup true
+   tljh-config reload
+
+Optional features
+=================
+
+More optional features are available on the `authenticator documentation <https://native-authenticator.readthedocs.io/en/latest/>`