The Xenioo variable colors_list holds a simple JSON built like this:
JSON.parse transform it into a full object that can be iterated to
create multiple chat buttons
var colors = JSON.parse( conversation.GetVariableValue( "colors_list" ) );
for( var i=0; i < colors.length; i++ ){
conversation.AddReplyPart(
"1" /* part type. 1 is button */,
colors[i].color, /* part text. We're using color name */
colors[i].colorid, /* command payload. Its the value we want in our postback. We are using ID */
"picked_color", /* postback target variable name. we can use this later in our chatbot */
"", /* button target behaviour. We leave it empty: its the current one */
"Color Selected" /* button target interaction. We go to "Selected Color" you see in the diagram */