diff --git a/inc/myco_objects.js b/inc/myco_objects.js
index 39994a4..4b6fcf3 100644
--- a/inc/myco_objects.js
+++ b/inc/myco_objects.js
@@ -337,6 +337,36 @@ function Group(uuid,name,data) {
     };
   }
   
+  this.getContributionsByCategory=function (category) {
+	  var ret={};
+	  for (uuid in this.contributions) {
+		  if (this.contributions[uuid].category==category.uuid) {
+			  ret[uuid]=this.contributions[uuid];
+		  }
+	  }
+	  return ret;
+  }
+  
+  this.findUnusedCategories=function() {
+	  var cats={};
+	  for (uuid in this.contributions) {
+		  cid=this.contributions[uuid].category;
+		  if ($.type(cats[cid])=='undefined') {
+			  cats[cid]=1;
+		  }
+		  else {
+			  cats[cid]++;
+		  }
+	  }
+	  var ret={};
+	  for (cid in this.categories) {
+		if ($.type(cats[cid])=='undefined') {
+			ret[cid]=this.categories[cid];
+		}
+	  }
+	  return ret;
+  }
+  
   /*
    * Categories
    */