Fixed README.md

Author: shadowy-pycoder

README.md

@@ -70,7 +70,7 @@ config = init_config(
     merge_configs = True,
     sections_ignored_on_merge = ['redis'], # do not include redis in your config
     convert_keys_to_snake_case = False,
-    add_underscore_prefix_to_keywords = False
+    add_underscore_prefix_to_keywords = False,
     raise_error_non_identifiers = False,
     validate_data_types = True,
     allow_extra_sections = True,