add migrations to fix groups

migrations/20150906_groups_remove_deleted_users.js

@@ -0,0 +1,51 @@
+/*
+ * Remove deleted accounts from groups
+ */
+
+var mongo = require('mongoskin');
+
+var dbserver = 'mongodb://url';
+var dbname = 'dbname';
+var countGroups = 0;
+var countUsers = 0;
+
+var db = mongo.db(dbserver + '/' + dbname + '?auto_reconnect');
+var dbUsers = db.collection('users');
+var dbGroups = db.collection('groups');
+
+console.log('Begins work on db');
+
+dbGroups.findEach({}, {_id: 1, members: 1}, {batchSize: 500}, function(err, group) {
+  if(err) throw err;
+  if(!group) return;
+
+  countGroups++;
+  console.log('Group: ', countGroups);
+
+  var members = group.members;
+
+  // Remove users who deleted their account
+  members.forEach(function(member){
+    dbUsers.count({_id: member}, function(err, count){
+      if(err) throw err;
+
+      if(count < 1) {
+        countUsers++;
+        console.log('User: ', countUsers);
+
+        dbGroups.update({
+          _id: group._id
+        }, {
+          $pull: {members: member},
+          $inc: {memberCount: -1}
+        }, {
+          multi: false
+        }, function(err, res){
+          if(err) throw err;
+
+          console.log('Updated: ', res);
+        });
+      }
+    });
+  });
+});