Creates a new transaction

Things to Note:

• Customer Key supplied can be [customer_key, customer_external_key, customer_email]

• Transaction amount can be 0 but cannot be [None, null, undefined]

• Transaction amount is in cents for whichever currency supplied

• Transaction key SHOULD be supplied (min 4 characters). This makes it easier to determine changes in your integration and allows transactions to be found internally

• A product_key or category_key can be supplied for customized reward generation

• Currency (currency) is the 3 character ISO code for a currency [USD, CAD, AUS]

• Transactions on customers created using the PartnerStackTest Partner will not generate rewards