Add tutotial doc

Author: duzumaki

docs/_images/application-register-device-code.png

@@ -9,4 +9,4 @@ Tutorials
    tutorial_03
    tutorial_04
    tutorial_05
-
+   tutorial_06

docs/_images/device-approve-deny.png

@@ -0,0 +1,86 @@
+Device authorization grant flow
+====================================================
+
+Scenario
+--------
+In :doc:`Part 1 <tutorial_01>` you created your own :term:`Authorization Server` and it's running along just fine.
+You have devices that your users have and those users need to authenticate the device against your
+:term:`Authorization Server` in order to make the required api calls.
+
+Device Authorization
+-----------------
+The OAuth 2.0 device authorization grant is designed for Internet
+connected devices that either lack a browser to perform a user-agent
+based authorization or are input constrained to the extent that
+requiring the user to input text in order to authenticate during the
+authorization flow is impractical.  It enables OAuth clients on such
+devices (like smart TVs, media consoles, digital picture frames, and
+printers) to obtain user authorization to access protected resources
+by using a user agent on a separate device.
+
+
+Point your browser to http://127.0.0.1:8000/o/applications/register/ create an application.
+
+Fill the form as show in the screenshot below, and before saving take note of ``Client id``.
+Make sure the client type is set to "Public". There are cases where a confidential client makes sense
+but generally, it assumed the device is unable to safely store the client secret.
+
+.. image:: _images/application-register-device-code.png
+   :alt: Device Authorization application registration
+
+Ensure the setting OAUTH_DEVICE_VERIFICATION_URI is set to a uri you want to come back
+verification_uri key in the response. This is what the device will use display
+to the user
+
+1: cd into the tests/app/idp directory
+
+.. code-block:: sh
+    curl --location 'http://127.0.0.1:8000/o/device-authorization/' \
+    --header 'Content-Type: application/x-www-form-urlencoded' \
+    --data-urlencode 'client_id={your application's client id}'
+
+The OAuth2 provider will return the following response:
+
+.. code-block:: json
+{
+    "verification_uri": "http://127.0.0.1:8000/o/device",
+    "expires_in": 1800,
+    "user_code": "A32RVADM",
+    "device_code": "G30j94v0kNfipD4KmGLTWeL4eZnKHm",
+    "interval": 5
+}
+
+Go to http://127.0.0.1:8000/o/device in browser
+
+.. image:: _images/device-enter-code-displayed.png
+
+Enter the code and it will redirect to the device-confirm endpoint
+
+/device-confirm endpoint [device polling is happening concurrently]
+-------------
+
+.. image:: _images/device-approve-deny.png
+
+/Device polling [user approving or denying happens concurrently]
+-------------
+Note: You should already have the /token endpoint implemented in your authorization server before this.
+
+Send this request (in the real world the device makes this request):
+
+.. code-block:: sh
+    curl --location 'http://localhost:8000/o/token/' \
+    --header 'Content-Type: application/x-www-form-urlencoded' \
+    --data-urlencode 'device_code={the device code from the device-authorization response}' \
+    --data-urlencode 'client_id={your application's client id}' \
+    --data-urlencode 'grant_type=urn:ietf:params:oauth:grant-type:device_code'
+
+.. code-block:: json
+{
+    "access_token": "SkJMgyL432P04nHDPyB63DEAM0nVxk",
+    "expires_in": 36000,
+    "token_type": "Bearer",
+    "scope": "openid",
+    "refresh_token": "Go6VumurDfFAeCeKrpCKPDtElV77id"
+}
+
+