Include list of users_with_permission in all folders response

This adds a list of user_ids of the users who have permission to view a folder
to the `get_template_folders_for_service` endpoint.

app/models.py

@@ -754,7 +754,8 @@ class TemplateFolder(db.Model):
             'id': self.id,
             'name': self.name,
             'parent_id': self.parent_id,
-            'service_id': self.service_id
+            'service_id': self.service_id,
+            'users_with_permission': self.get_users_with_permission()
         }
 
     def is_parent_of(self, other):
@@ -764,6 +765,12 @@ class TemplateFolder(db.Model):
             other = other.parent
         return False
 
+    def get_users_with_permission(self):
+        service_users = self.users
+        users_with_permission = [str(service_user.user_id) for service_user in service_users]
+
+        return users_with_permission
+
 
 template_folder_map = db.Table(
     'template_folder_map',