add migration script

Author: imcaizheng

README.md

@@ -67,6 +67,12 @@ The following parameters can be set in config files or in env variables:
 - Modify `DATABASE_URL` under `config/default.js` to meet your environment.
 - Run `npm run init-db` to create table(run `npm run init-db force` to force creating table)
 
+## DB Migration
+- `npm run migrate`: run any migration files which haven't run yet.
+- `npm run migrate:undo`: revert most recent migration.
+
+Configuration for migration is at `./config/config.json`.
+
 ## ElasticSearch Setup
 - Go to https://www.elastic.co/downloads/ download and install the elasticsearch.
 - Modify `esConfig` under `config/default.js` to meet your environment.

config/config.json

@@ -0,0 +1,23 @@
+{
+  "development": {
+    "username": "postgres",
+    "password": "postgres",
+    "database": "postgres",
+    "host": "127.0.0.1",
+    "dialect": "postgres"
+  },
+  "test": {
+    "username": "root",
+    "password": null,
+    "database": "database_test",
+    "host": "127.0.0.1",
+    "dialect": "mysql"
+  },
+  "production": {
+    "username": "root",
+    "password": null,
+    "database": "database_production",
+    "host": "127.0.0.1",
+    "dialect": "mysql"
+  }
+}

migrations/2021-01-04-make-some-resouce-booking-fields-optional.js

@@ -0,0 +1,18 @@
+/*
+ * Make ResourceBooking fields startDate, endDate, memberRate and customerRate optional.
+ */
+
+const targetFields = ['start_date', 'end_date', 'member_rate', 'customer_rate']
+
+module.exports = {
+  up: queryInterface => {
+    return Promise.all(targetFields.map(field =>
+      queryInterface.sequelize.query(`ALTER TABLE bookings.resource_bookings ALTER COLUMN ${field} DROP NOT NULL`)
+    ))
+  },
+  down: queryInterface => {
+    return Promise.all(targetFields.map(field =>
+      queryInterface.sequelize.query(`ALTER TABLE bookings.resource_bookings ALTER COLUMN ${field} SET NOT NULL`)
+    ))
+  }
+}