API v1 financial_transactions endpoints (#627)

spec/factories/financial_transaction.rb

@@ -0,0 +1,15 @@
+require 'factory_bot'
+
+FactoryBot.define do
+  factory :financial_transaction do
+    user
+    ordergroup
+    amount { rand(-99_999.00..99_999.00) }
+    note { Faker::Lorem.sentence }
+
+    # This builds a new type and class by default, while for normal financial
+    # transactions we'd use the default. This, however, is the easiest way to
+    # get the factory going. If you want equal types, specify it explicitly.
+    financial_transaction_type
+  end
+end