Generate user model
User has many pomodoros
Refactor importer response
Validate uniqueness of pomodoro's started_at and finished_at
Validate numericality of pomodoro's :started_at and :finished_at fields
Rewrite Importer class
Rewrote ClockworkTomatoImporter
Refactor importers spec
Refactor importer class
Refactor ClockworkTomatoImporter class
Separate importer specs