WIP Added model, migration and bulk upsert fnc.

app/seeders/20200121150443-initial-price-history.js

@@ -0,0 +1,19 @@
+"use strict";
+
+module.exports = {
+  up: (queryInterface, Sequelize) => {
+    // ??
+    const realEstateInitialData = await queryInterface.Sequelize.findall ();
+    const priceHistoryInitialData = realEstateInitialData.map ();
+    
+    return queryInterface.bulkInsert(
+      "PriceHistory",
+      priceHistoryInitialData,
+      {}
+    );
+  },
+
+  down: (queryInterface, Sequelize) => {
+    return queryInterface.bulkDelete("PriceHistory", null, {});
+  }
+};