added migration for db

server/migrations/File_AddHeightAndWidthColumn.js

@@ -0,0 +1,34 @@
+module.exports = {
+  up: (queryInterface, Sequelize) => {
+    // logic for transforming into the new state
+    const changeOne = queryInterface.addColumn(
+      'File',
+      'height',
+      {
+        type     : Sequelize.INTEGER,
+        allowNull: false,
+      }
+    );
+    const changeTwo = queryInterface.addColumn(
+      'File',
+      'width',
+      {
+        type     : Sequelize.INTEGER,
+        allowNull: false,
+      }
+    );
+    return Promise.all([changeOne, changeTwo]);
+  },
+  down: (queryInterface, Sequelize) => {
+    // logic for reverting the changes
+    const reversionOne = queryInterface.removeColumn(
+      'File',
+      'height'
+    );
+    const reversionTwo = queryInterface.removeColumn(
+      'File',
+      'width',
+    );
+    return Promise.all([reversionOne, reversionTwo]);
+  },
+};