diff --git a/lib/auth.lua b/lib/auth.lua
index ad3460a..9c4aeb9 100644
--- a/lib/auth.lua
+++ b/lib/auth.lua
@@ -49,6 +49,15 @@ function check_user_group(username, group)
     end
 end
 
+
+function list_to_string(list)
+    local str = ""
+    for i, v in ipairs(list) do
+        str = str .. v .. ", "
+    end
+    return str:sub(1, -3)
+end
+
 function list_user_groups(username)
     local data = {
         ["action"] = "list_groups",
@@ -71,7 +80,7 @@ function list_user_groups(username)
                 io.write("Invalid token\n")
                 return
             else
-                return msg
+                return list_to_string(msg)
             end
         end
     end