feat: add migration to add customer custom fields related tables

feat: create CustomerCustomField type on graphql
feat: add custom fields fetching to getCustomer and getCustomerList functions
feat: add mutations to interact with customer custom fields

migrations/1630624117042-customer-custom-fields.js

@@ -0,0 +1,23 @@
+var db = require('./db')
+
+exports.up = function (next) {
+  var sql = [
+    `CREATE TABLE custom_field_definitions (
+      id UUID PRIMARY KEY,
+      label TEXT NOT NULL UNIQUE,
+      active BOOLEAN DEFAULT true
+    )`,
+    `CREATE TABLE customer_custom_field_pairs (
+      customer_id UUID REFERENCES customers(id) NOT NULL,
+      custom_field_id UUID REFERENCES custom_field_definitions(id) NOT NULL,
+      value TEXT NOT NULL,
+      UNIQUE (customer_id, custom_field_id)
+    )`,
+  ]
+
+  db.multi(sql, next)
+}
+
+exports.down = function (next) {
+  next()
+}