add migrations to fix groups

migrations/20150906_groups_remove_empty.js

@@ -0,0 +1,21 @@
+/*
+ * Remove emoty groups
+ */
+
+var mongo = require('mongoskin');
+
+var dbserver = 'mongodb://url';
+var dbname = 'db';
+
+var db = mongo.db(dbserver + '/' + dbname + '?auto_reconnect');
+var dbGroups = db.collection('groups');
+
+console.log('Begins work on db');
+
+dbGroups.remove({
+  members: {$size: 0}
+}, function(err, res){
+  if(err) throw err;
+
+  console.log(res);
+});