Add documentation about gunicorn/config.py.

Fixes #896.

CONTRIBUTING.md

@@ -60,6 +60,10 @@ test suite on your branch before submitting a pull request.
 Make sure you include relevant updates or additions to documentation
 when creating or modifying features.
 
+If you are adding a new configuration option or updating an existing one,
+please do it in `gunicorn/config.py`, then run `make -C docs html` to update
+`docs/source/settings.rst`.
+
 Write clean code.
 
 Pull requests descriptions should be as clear as possible and include a

docs/source/settings.rst

@@ -1,6 +1,7 @@
-
 .. _settings:
 
+.. Please update gunicorn/config.py instead.
+
 Settings
 ========
 

gunicorn/config.py

@@ -3,6 +3,8 @@
 # This file is part of gunicorn released under the MIT license.
 # See the NOTICE for more information.
 
+# Please remember to run "make -C docs html" after update "desc" attributes.
+
 import copy
 import grp
 import inspect
@@ -457,7 +459,6 @@ def get_default_config_file():
     return None
 
 
-# Please remember to run "make html" in docs/ after update "desc" attributes.
 class ConfigFile(Setting):
     name = "config"
     section = "Config File"