add --color option

docs/source/user/options.rst

@@ -40,6 +40,8 @@ Index of Options
 
 - :option:`flake8 --quiet`
 
+- :option:`flake8 --color`
+
 - :option:`flake8 --count`
 
 - :option:`flake8 --diff`
@@ -181,6 +183,35 @@ Options and their Descriptions
 
         quiet = 1
 
+.. option:: --color
+
+    :ref:`Go back to index <top>`
+
+    Whether to use color in output. Defaults to ``auto``.
+
+    Possible options are ``auto``, ``always``, and ``never``.
+
+    This **can** be specified in config files.
+
+    When color is enabled, the following substitutions are enabled:
+
+    - ``%(bold)s``
+    - ``%(black)s``
+    - ``%(red)s``
+    - ``%(green)s``
+    - ``%(yellow)s``
+    - ``%(blue)s``
+    - ``%(magenta)s``
+    - ``%(cyan)s``
+    - ``%(white)s``
+    - ``%(reset)s``
+
+    Example config file usage:
+
+    .. code-block:: ini
+
+        color = never
+
 
 .. option:: --count