CH-152 add documentation

Author: filippomc

docs/accounts.md

@@ -178,8 +178,35 @@ harness:
 
 The above configuration will create 3 client roles under the "myapp" client and 2 users.
 
----
+
 **NOTE**
-Users and client roles are defined as a one-off initialization: they
+> Users and client roles are defined as a one-off initialization: they
 can be configured only on a new deployment and cannot be updated.
----
+
+
+### Retrieve user attributes Python API
+
+The auth API provides a way to get user attributes merged with groups attributes recursively.
+This allows us to define an attribute that is common for different users per group.
+A common use case is the definition of usage quotas, for which cloudharness provides a
+high level API.
+
+Example retrieve attributes:
+
+```Python
+from clouharness.auth.user_attributes import get_user_attributes
+
+attributes = get_user_attributes(kc_user_id_or_name)
+```
+
+The API provides parameters for filtering and provide a set of default values.
+
+The user quotas API also assumes that a set of default values can be specified at application level
+on `harness/quotas` and all quotas attributes begin with the `quota-` prefix.
+
+Example:
+
+```Python
+from clouharness.auth.quotas import get_user_quotas
+quotas = get_user_quotas(kc_user_id_or_name) # retrieves default quotas values from the current application
+```