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/support/securities_test_helper.rb

@@ -1,9 +1,19 @@
 module SecuritiesTestHelper
   def create_security(ticker, prices:)
+    security = Security.create!(
+      ticker: ticker,
+      exchange_mic: "XNAS"
+    )
+
     prices.each do |price|
-      Security::Price.create! ticker: ticker, date: price[:date], price: price[:price]
+      Security::Price.create!(
+        security: security,
+        date: price[:date],
+        price: price[:price],
+        currency: "USD"
+      )
     end
 
-    Security.create! ticker: ticker
+    security
   end
 end