Investment Portfolio Sync (#974)

* Add investment portfolio models

* Add portfolio to demo data

* Setup initial tests

* Rough sketch of sync logic

* Clean up trade sync logic

* Add trade validation

* Integrate trades into sync process

test/models/security/price_test.rb

@@ -0,0 +1,7 @@
+require "test_helper"
+
+class Security::PriceTest < ActiveSupport::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end