Consistent ordering for HTTP path keys (#159)

Author: bhperry

src/apispec_webframeworks/tornado.py

@@ -52,7 +52,7 @@ def _operations_from_methods(
         :param handler_class:
         :type handler_class: RequestHandler descendant
         """
-        for httpmethod in yaml_utils.PATH_KEYS:
+        for httpmethod in sorted(yaml_utils.PATH_KEYS):
             method = getattr(handler_class, httpmethod)
             docstring = method.__doc__ or ""
             operation_data = yaml_utils.load_yaml_from_docstring(docstring)