* for this sub-route.
* - Object: Hash of HTTP-method (get, put, post, del, or all) to the name
* of a method on this Controller.
+ *
+ * Example:
+ * { '/foo' => 'foo',
+ * '/bar' => {'get' => 'get_bar', 'del' => 'delete_bar' },
+ * }
+ * If this mapping is in a controller with name 'nonya', then
+ * GET '/nonya/foo' -> NonyaController.foo(),
+ * GET '/nonya/bar' -> NonyaController.get_bar()
+ * DELETE '/nonya/bar' -> NonyaController.delete_bar()
+ *
* @type Object
*/
mapping : null