update doc for the new workers

docs/source/design.rst

@@ -49,6 +49,19 @@ There's also a Tornado worker class. It can be used to write applications using
 the Tornado framework. Although the Tornado workers are capable of serving a
 WSGI application, this is not a recommended configuration.
 
+AsyncIO Workers
+---------------
+
+These workers are compatible with python3. You have two kind of workers.
+
+The worker `gthread` is a threaded worker. It accepts connections in the
+main loop, accepted connections are are added to the thread pool as a
+connection job. On keepalive connections are put back in the loop
+waiting for an event. If no event happen after the keep alive timeout,
+the connection is closed.
+
+The worker `gaiohttp` is a full asyncio worker using [aiohttp](https://github.com/KeepSafe/aiohttp).
+
 Choosing a Worker Type
 ======================
 

docs/source/settings.rst

@@ -396,7 +396,7 @@ temporary directory.
 secure_scheme_headers
 ~~~~~~~~~~~~~~~~~~~~~
 
-* ``{'X-FORWARDED-SSL': 'on', 'X-FORWARDED-PROTOCOL': 'ssl', 'X-FORWARDED-PROTO': 'https'}``
+* ``{'X-FORWARDED-SSL': 'on', 'X-FORWARDED-PROTO': 'https', 'X-FORWARDED-PROTOCOL': 'ssl'}``
 
 A dictionary containing headers and values that the front-end proxy
 uses to indicate HTTPS requests. These tell gunicorn to set