Update docstring for util.read_config

src/milla/util.py

@@ -72,6 +72,8 @@ def read_config(filename, defaults=None):
     '''Parse an ini file into a nested dictionary
 
     :param string filename: Path to the ini file to read
+    :param dict defaults: (Optional) A mapping of default values that can be
+       used for interpolation when reading the configuration file
     :returns: A dictionary whose keys correspond to the section and
        option, joined with a dot character (.)
 
@@ -101,6 +103,7 @@ def read_config(filename, defaults=None):
     This dictionary can be used to configure an :py:class:`~milla.Application`
     instance by using the ``update`` method::
 
+        config = milla.util.read_config('superheros.ini')
         app = milla.Application(router)
         app.config.update(config)
     '''