Adds business intelligence endpoint 'GET /api/v1/merchants/:id/favorite_customer' that returns the customer who has conducted the most total number of successful transactions.
-adds custom route
-adds favorite_customer controller for merchants
-adds custom method (favorite_customer) to merchants model
-all tests/spec harness passing
Adds business intelligence endpoint 'GET /api/v1/merchants/:id/favorite_customer' that returns the customer who has conducted the most total number of successful transactions. -adds custom route -adds favorite_customer controller for merchants -adds custom method (favorite_customer) to merchants model -all tests/spec harness passing