Export resource_class_map and fix bug in Role.add_user() (#1047)

The reason for exporting resource_class_map is to allow an external module to support additional resource types without the need to edit resources.py (I had edited it previously but this became a maintenance nightmare).

The Role.add_user() bug is (I hope) an obvious one: the groups argument was ignored.

jira/resources.py

@@ -46,6 +46,7 @@
     "Customer",
     "ServiceDesk",
     "RequestType",
+    "resource_class_map",
 )
 
 logging.getLogger("jira").addHandler(logging.NullHandler())
@@ -960,7 +961,7 @@ def add_user(
         if groups is not None and isinstance(groups, str):
             groups = (groups,)
 
-        data = {"user": users}  # FIXME: groups is not used.
+        data = {"user": users, "group": groups}
         self._session.post(self.self, data=json.dumps(data))