Add warning to not play around with users and groups

source/3/3.2/3.2.15/users_and_groups.rst

@@ -13,7 +13,11 @@ The :guilabel:`users` tab lets you manage Users.To create a new useage create a
 
 To change your users password you can press on the button with a key and enter the new password and enter new password and then use a password to authenticate that you have permission to do this. 
 
-The :guilabel:`Groups` tabs lets you see info on groups and change properties. The :guilabel:`Name` field shows the name of the group. The :guilabel:`Group ID` shows the numeric group id of the group in the name field. The :guilabel:`Members` show the members of the current group.   
+The :guilabel:`Groups` tabs lets you see info on groups and change properties. The :guilabel:`Name` field shows the name of the group. The :guilabel:`Group ID` shows the numeric group id of the group in the name field. The :guilabel:`Members` show the members of the current group. 
+
+.. warning::
+
+   Changing user and group permissions without knowing what you are doing could break your system.
 
 Screenshot
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