add a minimal ini file for pytest

pytest.ini

@@ -0,0 +1,9 @@
+[pytest]
+minversion = 3.3
+python_files = test_*.py
+markers =
+    gen_test: marks an async tornado test
+    group: mark as a test for groups
+    services: mark as a services test
+    user: mark as a test for a user
+    slow: mark a test as slow