Coloring task based on their priority [SOLVED]

Hello, i have a selection box and some levels of priority as the options
gantt.serverList(“priority”, [
{ label:“Critical”, key:0, backgroundColor:“red”},
{ label:“Important”, key:1, backgroundColor:“orange”},
{ label:“Normal”, key:2, backgroundColor:“yellow”},
{ label:“Low”, key:3, backgroundColor:“green”},
{ label:“None”, key:4, backgroundColor:“blue”}]);

but i don’t know how to make these colors appear on my task, i already this page :
and still don’t know what to do :worried:

i change the priority option lil bit, and here is the snippet, is already include color changed if task already complete