benedmunds/CodeIgniter-Ion-Auth — pull request #308 by Dentxinho (2012-09-20 18:11:29+00:00)
Title: Cache users groups on demand to prevent multiple sql queries 

Several calls to ```in_group()``` don't query the database several times anymore.
Added a on-demand cache of users_groups that looks like this:
```[user_id] => array( [group_id] => [group_name], [group2_id] => [group2_name] )```

As a new query was added on ```add_to_group()```, on-demand caching of groups was added too. (note: only ```[group_id] => [group_name]```).

Fixes #307