Workaround for initialize method collision

- Issue #6
- Opened Issue #8
- Temporarily addressed method name collision between Sequel::Model and
  Pomodori::Configuration by no longer including Pomodori::Configuration and
  instead, getting the config from the database object
- Not happy with this, except it moves me forward
Dropped final piece into place to see a Pomodoro obj instantiated

- Fixes #6
- Addressed issue with migrations and factories being out-of-sync
    - Had to add started_at to migration
    - Had to add created_at to factory