Organize model
Remove explicit ID passing, refactor time formatting
Refactor change method, which will be deprecated in API
Add association tests
Merge pull request #109 from tuxedio/c-refactor-itinerary-items

Refactor itinerary items
Tighten up data associations
Merge pull request #110 from tuxedio/c-secure-schema

Tighten up data associations
Remove start_time and end_time from activities migrations
Merge pull request #111 from tuxedio/c-secure-schema

Remove start_time and end_time from activities migrations
fixed trip_id to trip