now can choose which topics to bag in the control pannel

backend/js/Topic.js

@@ -0,0 +1,12 @@
+function Topic (name) {
+    this.name = name;
+    this.bag = true;
+    this.type = "";
+}
+
+Array.prototype.indexOfTopic = function(name) {
+    for (var i = 0; i < this.length; i++)
+        if (this[i].name == name)
+            return i;
+    return -1;
+}