add migration script to fix rogue parties

migrations/20130508_fix_duff_party_subscriptions.js

@@ -0,0 +1,36 @@
+/**
+ * 745612d and fedc5b6 added a db-subscription optimization to the initial subscribe.
+ * However, it requires the user only be to one party. That should be the case anyway, but user.party.current was letting
+ * us look past the fact that a user was erroneously subscribed to multiple parties. This fixes
+ *
+ * mongo habitrpg ./node_modules/underscore/underscore.js ./migrations/20130508_fix_duff_party_subscriptions.js
+ */
+
+
+// since our primary subscription will first hit parties now, we *definitely* need an index there
+db.parties.ensureIndex( { 'members': 1,  'background': 1} );
+
+db.parties.find().forEach(function(party){
+
+    if(!party.members) {
+        return db.parties.remove({_id:party._id});
+    }
+
+    // Find all members
+    db.users.find( {_id: {$in:party.members} }, {_id:1,party:1} ).forEach(function(user){
+        // user somehow is subscribed to this party in the background, but they're it's not their primary party
+        if (user.party && user.party.current !== party._id) {
+            i = party.members.indexOf(user._id);
+            party.members.splice(i, 1);
+        }
+
+        // if after we remove the user, the party is empty - delete this party
+        if (_.isEmpty(party.members)) {
+            db.parties.remove({_id:party._id});
+
+        // else just set it
+        } else {
+            db.parties.update({_id:party._id}, {$set:{members:party.members}});
+        }
+    })
+})