how bout

alembic.ini

@@ -12,7 +12,7 @@ file_template = %%(year)d_%%(month).2d_%%(day).2d-%%(rev)s_%%(slug)s
 
 # sys.path path, will be prepended to sys.path if present.
 # defaults to the current working directory.
-; prepend_sys_path =
+prepend_sys_path = .
 
 # timezone to use when rendering the date within the migration file
 # as well as the filename.