Bug fix
Working fulfillment + minor updates - still need improvements
Improve Purchase model interface
Better Currency interface
Add prepare! method to all item class to create fulfillment records
Add status, fulfilled_at to orders, fulfillments table
Update Fulfillment interface
Add fulfillment preparation behavior for item classes
Update fulfillable spec
Add various seed records
Fix currency conversion bug
Use proper context for interface spec
Add Enum module
Include Enum in Fulfillment and Order classes
Remove unnecessary validations
Move shared modules into shared folders
Explicitly require dependencies
Working fulfillment
Reorganize spec folder
Fix typo