Minor improvement to docs

docs/config.rst

@@ -12,6 +12,8 @@ Example::
   [flake8]
   ignore = E226,E302,E41
   max-line-length = 160
+  exclude = tests/*
+  max-complexity = 10
 
 Per-Project
 -----------
@@ -26,3 +28,27 @@ Default
 If the ``ignore`` option is not in the configuration and not in the arguments,
 only the error codes ``E226`` and ``E241/E242`` are ignored
 (see the :ref:`warning and error codes <error-codes>`).
+
+Settings
+--------
+
+This is a (likely incomplete) list of settings that can be used in your config
+file. In general, any settings that pep8 supports we also support and we add
+the ability to set ``max-complexity`` as well.
+
+- ``exclude``: comma-separated filename and glob patterns
+  default: ``.svn,CVS,.bzr,.hg,.git,__pycache``
+
+- ``filename``: comma-separated filename and glob patterns
+  default: ``*.py``
+
+- ``select``: select errors and warnings to enable which are off by default
+
+- ``ignore``: skip errors or warnings
+
+- ``max-line-length``: set maximum allowed line length
+  default: 79
+
+- ``format``: set the error format
+
+- ``max-complexity``: McCabe complexity threshold