Create a new txnRunner for each operation, and change constrcutors to just require a database
Add code comments
Merge pull request #1 from wallyworld/txn-refactor

Refactor txnRunner usage
Update to use new juju/txn runne
Merge pull request #2 from wallyworld/txnrunner-change

Update to use new juju/txn runner
Update to gopkg.in/mgo.v2 repository

labix.org/v2/mgo is no longer maintained.