Added data format to requirements

Author: rofrano

lab/test_counter.py

@@ -5,6 +5,7 @@
 - The API must be RESTful.
 - The endpoint must be called `/counters`.
 - When creating a counter, you must specify the name in the path.
+- The data returned should be this {"name":"some_name", "counter:0}
 - Duplicate names must return a 409 conflict error code.
 - The service must be able to update a counter by name.
 - The service must be able to get a counter's current value.