First pass at security price reference (#1388)

* First pass at security price reference

* Data cleanup

* Synth security fetching does better with a mic_code

* Update test suite

😭

* Update schema.rb

* Update generator.rb

test/models/account/holding_test.rb

@@ -58,7 +58,7 @@ class Account::HoldingTest < ActiveSupport::TestCase
     end
 
     def create_holding(security, date, qty)
-      price = Security::Price.find_by(date: date, ticker: security.ticker).price
+      price = Security::Price.find_by(date: date, security: security).price
 
       @account.holdings.create! \
         date: date,